diff --git a/src/ContainerInterface.php b/src/ContainerInterface.php
index c64493b..218139b 100644
--- a/src/ContainerInterface.php
+++ b/src/ContainerInterface.php
@@ -3,10 +3,31 @@
 namespace ByJoby\HTML;
 
 use Stringable;
-use Traversable;
 
 interface ContainerInterface extends Stringable
 {
     /** @return array<int,NodeInterface> */
     public function children(): array;
+
+    public function addChild(
+        NodeInterface|Stringable|string $child,
+        bool $prepend = false,
+        bool $skip_sanitize = false
+    ): static;
+
+    public function removeChild(
+        NodeInterface|Stringable|string $child
+    ): static;
+
+    public function addChildBefore(
+        NodeInterface|Stringable|string $new_child,
+        NodeInterface|Stringable|string $before_child,
+        bool $skip_sanitize = false
+    ): static;
+
+    public function addChildAfter(
+        NodeInterface|Stringable|string $new_child,
+        NodeInterface|Stringable|string $after_child,
+        bool $skip_sanitize = false
+    ): static;
 }
diff --git a/src/ContainerMutableInterface.php b/src/ContainerMutableInterface.php
deleted file mode 100644
index bfa8a27..0000000
--- a/src/ContainerMutableInterface.php
+++ /dev/null
@@ -1,30 +0,0 @@
-<?php
-
-namespace ByJoby\HTML;
-
-use Stringable;
-
-interface ContainerMutableInterface extends ContainerInterface
-{
-    public function addChild(
-        NodeInterface|Stringable|string $child,
-        bool $prepend = false,
-        bool $skip_sanitize = false
-    ): static;
-
-    public function removeChild(
-        NodeInterface|Stringable|string $child
-    ): static;
-
-    public function addChildBefore(
-        NodeInterface|Stringable|string $new_child,
-        NodeInterface|Stringable|string $before_child,
-        bool $skip_sanitize = false
-    ): static;
-
-    public function addChildAfter(
-        NodeInterface|Stringable|string $new_child,
-        NodeInterface|Stringable|string $after_child,
-        bool $skip_sanitize = false
-    ): static;
-}
diff --git a/src/Containers/DocumentTags/TitleTag.php b/src/Containers/DocumentTags/TitleTag.php
index 57efdb0..cb470dc 100644
--- a/src/Containers/DocumentTags/TitleTag.php
+++ b/src/Containers/DocumentTags/TitleTag.php
@@ -25,11 +25,6 @@ class TitleTag implements TitleTagInterface
         return $this->title;
     }
 
-    public function detach(): static
-    {
-        throw new Exception('Not allowed to detach TitleTag');
-    }
-
     public function __toString(): string
     {
         return '<title>' . $this->title() . '</title>';
diff --git a/src/Containers/Fragment.php b/src/Containers/Fragment.php
index 4f5214b..66c14c6 100644
--- a/src/Containers/Fragment.php
+++ b/src/Containers/Fragment.php
@@ -3,7 +3,6 @@
 namespace ByJoby\HTML\Containers;
 
 use ByJoby\HTML\NodeInterface;
-use ByJoby\HTML\Traits\ContainerMutableTrait;
 use ByJoby\HTML\Traits\ContainerTrait;
 use Stringable;
 use Traversable;
@@ -11,7 +10,6 @@ use Traversable;
 class Fragment implements FragmentInterface
 {
     use ContainerTrait;
-    use ContainerMutableTrait;
 
     /**
      * @param null|array<mixed,string|Stringable|NodeInterface>|Traversable<mixed,string|Stringable|NodeInterface>|null $children
diff --git a/src/Containers/FragmentInterface.php b/src/Containers/FragmentInterface.php
index 7215815..39288bd 100644
--- a/src/Containers/FragmentInterface.php
+++ b/src/Containers/FragmentInterface.php
@@ -3,8 +3,7 @@
 namespace ByJoby\HTML\Containers;
 
 use ByJoby\HTML\ContainerInterface;
-use ByJoby\HTML\ContainerMutableInterface;
 
-interface FragmentInterface extends DocumentInterface, ContainerMutableInterface
+interface FragmentInterface extends DocumentInterface, ContainerInterface
 {
 }
diff --git a/src/Containers/GenericHtmlDocument.php b/src/Containers/GenericHtmlDocument.php
index ccfe18b..1eb33c0 100644
--- a/src/Containers/GenericHtmlDocument.php
+++ b/src/Containers/GenericHtmlDocument.php
@@ -2,17 +2,18 @@
 
 namespace ByJoby\HTML\Containers;
 
-use ByJoby\HTML\Containers\DocumentTags\BodyTag;
 use ByJoby\HTML\Containers\DocumentTags\BodyTagInterface;
 use ByJoby\HTML\Containers\DocumentTags\Doctype;
 use ByJoby\HTML\Containers\DocumentTags\DoctypeInterface;
-use ByJoby\HTML\Containers\DocumentTags\HeadTag;
 use ByJoby\HTML\Containers\DocumentTags\HeadTagInterface;
 use ByJoby\HTML\Containers\DocumentTags\HtmlTag;
 use ByJoby\HTML\Containers\DocumentTags\HtmlTagInterface;
+use ByJoby\HTML\Traits\ContainerTrait;
 
 class GenericHtmlDocument implements HtmlDocumentInterface
 {
+    use ContainerTrait;
+
     /** @var DoctypeInterface */
     protected $doctype;
     /** @var HtmlTagInterface */
@@ -20,8 +21,10 @@ class GenericHtmlDocument implements HtmlDocumentInterface
 
     public function __construct()
     {
-        $this->doctype = (new Doctype)->setDocument($this);
-        $this->html = (new HtmlTag)->setDocument($this);
+        $this->doctype = (new Doctype);
+        $this->html = (new HtmlTag);
+        $this->addChild($this->doctype);
+        $this->addChild($this->html);
     }
 
     public function doctype(): DoctypeInterface
diff --git a/src/Helpers/Attributes.php b/src/Helpers/Attributes.php
index 07d76bb..d014900 100644
--- a/src/Helpers/Attributes.php
+++ b/src/Helpers/Attributes.php
@@ -12,12 +12,12 @@ use Traversable;
 /**
  * Holds and validates a set of HTML attribute name/value pairs for use in tags.
  * 
- * @implements ArrayAccess<string,null|string|Stringable>
- * @implements IteratorAggregate<string,null|string|Stringable>
+ * @implements ArrayAccess<string,bool|string|Stringable>
+ * @implements IteratorAggregate<string,bool|string|Stringable>
  */
 class Attributes implements IteratorAggregate, ArrayAccess
 {
-    /** @var array<string,null|string|Stringable> */
+    /** @var array<string,bool|string|Stringable> */
     protected $array = [];
     /** @var bool */
     protected $sorted = true;
@@ -25,7 +25,7 @@ class Attributes implements IteratorAggregate, ArrayAccess
     protected $disallowed = [];
 
     /**
-     * @param null|array<string,null|string|Stringable> $array 
+     * @param null|array<string,bool|string|Stringable> $array 
      * @param array<mixed,string> $disallowed
      * @return void 
      */
@@ -59,6 +59,13 @@ class Attributes implements IteratorAggregate, ArrayAccess
         $this->array[$offset] = $value;
     }
 
+    public function string(string $offset): null|string
+    {
+        $value = $this->offsetGet($offset);
+        if (is_string($value)) return $value;
+        else return null;
+    }
+
     function offsetUnset(mixed $offset): void
     {
         $offset = static::sanitizeOffset($offset);
@@ -66,7 +73,7 @@ class Attributes implements IteratorAggregate, ArrayAccess
     }
 
     /**
-     * @return array<string,null|string|Stringable>
+     * @return array<string,bool|string|Stringable>
      */
     function getArray(): array
     {
diff --git a/src/Html5/Tags/BaseTag.php b/src/Html5/Tags/BaseTag.php
index 147e1cb..da499d1 100644
--- a/src/Html5/Tags/BaseTag.php
+++ b/src/Html5/Tags/BaseTag.php
@@ -11,12 +11,13 @@ class BaseTag extends AbstractTag implements MetadataContent
 
     public function href(): null|string
     {
-        return $this->attributes()['href'];
+        return $this->attributes()->string('href');
     }
 
     public function setHref(null|string $href): static
     {
-        $this->attributes()['href'] = $href;
+        if (!$href) $this->attributes()['href'] = false;
+        else $this->attributes()['href'] = $href;
         return $this;
     }
 
@@ -28,12 +29,13 @@ class BaseTag extends AbstractTag implements MetadataContent
 
     public function target(): null|string
     {
-        return $this->attributes()['target'];
+        return $this->attributes()->string('target');
     }
 
     public function setTarget(null|string $target): static
     {
-        $this->attributes()['target'] = $target;
+        if (!$target) $this->attributes()['target'] = false;
+        else $this->attributes()['target'] = $target;
         return $this;
     }
 
diff --git a/src/Html5/Tags/LinkTag.php b/src/Html5/Tags/LinkTag.php
index 608a8e4..b8cff37 100644
--- a/src/Html5/Tags/LinkTag.php
+++ b/src/Html5/Tags/LinkTag.php
@@ -11,12 +11,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function rel(): null|string
     {
-        return $this->attributes()['rel'];
+        return $this->attributes()->string('rel');
     }
 
     public function setRel(null|string $rel): static
     {
-        $this->attributes()['rel'] = $rel;
+        if (!$rel) $this->attributes()['rel'] = false;
+        else $this->attributes()['rel'] = $rel;
         return $this;
     }
 
@@ -28,12 +29,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function as(): null|string
     {
-        return $this->attributes()['as'];
+        return $this->attributes()->string('as');
     }
 
     public function setAs(null|string $as): static
     {
-        $this->attributes()['as'] = $as;
+        if (!$as) $this->attributes()['as'] = false;
+        else $this->attributes()['as'] = $as;
         return $this;
     }
 
@@ -45,12 +47,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function crossorigin(): null|string
     {
-        return $this->attributes()['crossorigin'];
+        return $this->attributes()->string('crossorigin');
     }
 
     public function setCrossorigin(null|string $crossorigin): static
     {
-        $this->attributes()['crossorigin'] = $crossorigin;
+        if (!$crossorigin) $this->attributes()['crossorigin'] = false;
+        else $this->attributes()['crossorigin'] = $crossorigin;
         return $this;
     }
 
@@ -62,12 +65,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function href(): null|string
     {
-        return $this->attributes()['href'];
+        return $this->attributes()->string('href');
     }
 
     public function setHref(null|string $href): static
     {
-        $this->attributes()['href'] = $href;
+        if (!$href) $this->attributes()['href'] = false;
+        else $this->attributes()['href'] = $href;
         return $this;
     }
 
@@ -79,12 +83,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function hreflang(): null|string
     {
-        return $this->attributes()['hreflang'];
+        return $this->attributes()->string('hreflang');
     }
 
     public function setHreflang(null|string $hreflang): static
     {
-        $this->attributes()['hreflang'] = $hreflang;
+        if (!$hreflang) $this->attributes()['hreflang'] = false;
+        else $this->attributes()['hreflang'] = $hreflang;
         return $this;
     }
 
@@ -96,12 +101,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function imagesizes(): null|string
     {
-        return $this->attributes()['imagesizes'];
+        return $this->attributes()->string('imagesizes');
     }
 
     public function setImagesizes(null|string $imagesizes): static
     {
-        $this->attributes()['imagesizes'] = $imagesizes;
+        if (!$imagesizes) $this->attributes()['imagesizes'] = false;
+        else $this->attributes()['imagesizes'] = $imagesizes;
         return $this;
     }
 
@@ -113,12 +119,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function imagesrcset(): null|string
     {
-        return $this->attributes()['imagesrcset'];
+        return $this->attributes()->string('imagesrcset');
     }
 
     public function setImagesrcset(null|string $imagesrcset): static
     {
-        $this->attributes()['imagesrcset'] = $imagesrcset;
+        if (!$imagesrcset) $this->attributes()['imagesrcset'] = false;
+        else $this->attributes()['imagesrcset'] = $imagesrcset;
         return $this;
     }
 
@@ -130,12 +137,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function integrity(): null|string
     {
-        return $this->attributes()['integrity'];
+        return $this->attributes()->string('integrity');
     }
 
     public function setIntegrity(null|string $integrity): static
     {
-        $this->attributes()['integrity'] = $integrity;
+        if (!$integrity) $this->attributes()['integrity'] = false;
+        else $this->attributes()['integrity'] = $integrity;
         return $this;
     }
 
@@ -147,12 +155,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function media(): null|string
     {
-        return $this->attributes()['media'];
+        return $this->attributes()->string('media');
     }
 
     public function setMedia(null|string $media): static
     {
-        $this->attributes()['media'] = $media;
+        if (!$media) $this->attributes()['media'] = false;
+        else $this->attributes()['media'] = $media;
         return $this;
     }
 
@@ -164,12 +173,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function referrerpolicy(): null|string
     {
-        return $this->attributes()['referrerpolicy'];
+        return $this->attributes()->string('referrerpolicy');
     }
 
     public function setReferrerpolicy(null|string $referrerpolicy): static
     {
-        $this->attributes()['referrerpolicy'] = $referrerpolicy;
+        if (!$referrerpolicy) $this->attributes()['referrerpolicy'] = false;
+        else $this->attributes()['referrerpolicy'] = $referrerpolicy;
         return $this;
     }
 
@@ -181,12 +191,13 @@ class LinkTag extends AbstractTag implements MetadataContent
 
     public function type(): null|string
     {
-        return $this->attributes()['type'];
+        return $this->attributes()->string('type');
     }
 
     public function setType(null|string $type): static
     {
-        $this->attributes()['type'] = $type;
+        if (!$type) $this->attributes()['type'] = false;
+        else $this->attributes()['type'] = $type;
         return $this;
     }
 
diff --git a/src/Html5/Tags/MetaTag.php b/src/Html5/Tags/MetaTag.php
index 8c3d347..2a9dc62 100644
--- a/src/Html5/Tags/MetaTag.php
+++ b/src/Html5/Tags/MetaTag.php
@@ -11,12 +11,13 @@ class MetaTag extends AbstractTag implements MetadataContent
 
     public function name(): null|string
     {
-        return $this->attributes()['name'];
+        return $this->attributes()->string('name');
     }
 
     public function setName(null|string $name): static
     {
-        $this->attributes()['name'] = $name;
+        if (!$name) $this->attributes()['name'] = false;
+        else $this->attributes()['name'] = $name;
         return $this;
     }
 
@@ -28,12 +29,13 @@ class MetaTag extends AbstractTag implements MetadataContent
 
     public function content(): null|string
     {
-        return $this->attributes()['content'];
+        return $this->attributes()->string('content');
     }
 
     public function setContent(null|string $content): static
     {
-        $this->attributes()['content'] = $content;
+        if (!$content) $this->attributes()['content'] = false;
+        else $this->attributes()['content'] = $content;
         return $this;
     }
 
@@ -45,12 +47,13 @@ class MetaTag extends AbstractTag implements MetadataContent
 
     public function httpEquiv(): null|string
     {
-        return $this->attributes()['http-equiv'];
+        return $this->attributes()->string('http-equiv');
     }
 
     public function setHttpEquiv(null|string $http_equiv): static
     {
-        $this->attributes()['http-equiv'] = $http_equiv;
+        if (!$http_equiv) $this->attributes()['http-equiv'] = false;
+        else $this->attributes()['http-equiv'] = $http_equiv;
         return $this;
     }
 
@@ -62,12 +65,13 @@ class MetaTag extends AbstractTag implements MetadataContent
 
     public function charset(): null|string
     {
-        return $this->attributes()['charset'];
+        return $this->attributes()->string('charset');
     }
 
     public function setCharset(null|string $charset): static
     {
-        $this->attributes()['charset'] = $charset;
+        if (!$charset) $this->attributes()['charset'] = false;
+        else $this->attributes()['charset'] = $charset;
         return $this;
     }
 
diff --git a/src/Html5/Tags/ScriptTag.php b/src/Html5/Tags/ScriptTag.php
index a575389..b53c22f 100644
--- a/src/Html5/Tags/ScriptTag.php
+++ b/src/Html5/Tags/ScriptTag.php
@@ -13,36 +13,35 @@ class ScriptTag extends AbstractContentTag implements MetadataContent, PhrasingC
 
     public function setAsync(bool $async): static
     {
-        if ($async) $this->attributes()['async'] = null;
-        else unset($this->attributes()['async']);
+        $this->attributes()['async'] = $async;
         return $this;
     }
 
     public function async(): bool
     {
-        return isset($this->attributes()['async']);
+        return !!$this->attributes()['async'];
     }
 
     public function setDefer(bool $defer): static
     {
-        if ($defer) $this->attributes()['defer'] = null;
-        else unset($this->attributes()['defer']);
+        $this->attributes()['defer'] = $defer;
         return $this;
     }
 
     public function defer(): bool
     {
-        return isset($this->attributes()['defer']);
+        return !!$this->attributes()['defer'];
     }
 
     public function crossorigin(): null|string
     {
-        return $this->attributes()['crossorigin'];
+        return $this->attributes()->string('crossorigin');
     }
 
     public function setCrossorigin(null|string $crossorigin): static
     {
-        $this->attributes()['crossorigin'] = $crossorigin;
+        if (!$crossorigin) $this->attributes()['crossorigin'] = false;
+        else $this->attributes()['crossorigin'] = $crossorigin;
         return $this;
     }
 
@@ -54,12 +53,13 @@ class ScriptTag extends AbstractContentTag implements MetadataContent, PhrasingC
 
     public function integrity(): null|string
     {
-        return $this->attributes()['integrity'];
+        return $this->attributes()->string('integrity');
     }
 
     public function setIntegrity(null|string $integrity): static
     {
-        $this->attributes()['integrity'] = $integrity;
+        if (!$integrity) $this->attributes()['integrity'] = false;
+        else $this->attributes()['integrity'] = $integrity;
         return $this;
     }
 
@@ -69,31 +69,26 @@ class ScriptTag extends AbstractContentTag implements MetadataContent, PhrasingC
         return $this;
     }
 
-    public function nomodule(): null|string
-    {
-        return $this->attributes()['nomodule'];
-    }
-
-    public function setNomodule(null|string $nomodule): static
+    public function setNomodule(bool $nomodule): static
     {
         $this->attributes()['nomodule'] = $nomodule;
         return $this;
     }
 
-    public function unsetNomodule(): static
+    public function nomodule(): bool
     {
-        unset($this->attributes()['nomodule']);
-        return $this;
+        return !!$this->attributes()['nomodule'];
     }
 
     public function nonce(): null|string
     {
-        return $this->attributes()['nonce'];
+        return $this->attributes()->string('nonce');
     }
 
     public function setNonce(null|string $nonce): static
     {
-        $this->attributes()['nonce'] = $nonce;
+        if (!$nonce) $this->attributes()['nonce'] = false;
+        else $this->attributes()['nonce'] = $nonce;
         return $this;
     }
 
@@ -105,12 +100,13 @@ class ScriptTag extends AbstractContentTag implements MetadataContent, PhrasingC
 
     public function referrerpolicy(): null|string
     {
-        return $this->attributes()['referrerpolicy'];
+        return $this->attributes()->string('referrerpolicy');
     }
 
     public function setReferrerpolicy(null|string $referrerpolicy): static
     {
-        $this->attributes()['referrerpolicy'] = $referrerpolicy;
+        if (!$referrerpolicy) $this->attributes()['referrerpolicy'] = false;
+        else $this->attributes()['referrerpolicy'] = $referrerpolicy;
         return $this;
     }
 
@@ -122,12 +118,13 @@ class ScriptTag extends AbstractContentTag implements MetadataContent, PhrasingC
 
     public function src(): null|string
     {
-        return $this->attributes()['src'];
+        return $this->attributes()->string('src');
     }
 
     public function setSrc(null|string $src): static
     {
-        $this->attributes()['src'] = $src;
+        if (!$src) $this->attributes()['src'] = false;
+        else $this->attributes()['src'] = $src;
         return $this;
     }
 
@@ -139,12 +136,13 @@ class ScriptTag extends AbstractContentTag implements MetadataContent, PhrasingC
 
     public function type(): null|string
     {
-        return $this->attributes()['type'];
+        return $this->attributes()->string('type');
     }
 
     public function setType(null|string $type): static
     {
-        $this->attributes()['type'] = $type;
+        if (!$type) $this->attributes()['type'] = false;
+        else $this->attributes()['type'] = $type;
         return $this;
     }
 
diff --git a/src/Html5/Tags/StyleTag.php b/src/Html5/Tags/StyleTag.php
index 511bbf8..9d2656a 100644
--- a/src/Html5/Tags/StyleTag.php
+++ b/src/Html5/Tags/StyleTag.php
@@ -11,12 +11,13 @@ class StyleTag extends AbstractContentTag implements MetadataContent
 
     public function media(): null|string
     {
-        return $this->attributes()['media'];
+        return $this->attributes()->string('media');
     }
 
     public function setMedia(null|string $media): static
     {
-        $this->attributes()['media'] = $media;
+        if (!$media) $this->attributes()['media'] = false;
+        else $this->attributes()['media'] = $media;
         return $this;
     }
 
@@ -28,12 +29,13 @@ class StyleTag extends AbstractContentTag implements MetadataContent
 
     public function nonce(): null|string
     {
-        return $this->attributes()['nonce'];
+        return $this->attributes()->string('nonce');
     }
 
     public function setNonce(null|string $nonce): static
     {
-        $this->attributes()['nonce'] = $nonce;
+        if (!$nonce) $this->attributes()['nonce'] = false;
+        else $this->attributes()['nonce'] = $nonce;
         return $this;
     }
 
diff --git a/src/NodeInterface.php b/src/NodeInterface.php
index 1e8f608..3ea28d2 100644
--- a/src/NodeInterface.php
+++ b/src/NodeInterface.php
@@ -3,21 +3,27 @@
 namespace ByJoby\HTML;
 
 use ByJoby\HTML\Containers\DocumentInterface;
+use ByJoby\HTML\Tags\TagInterface;
 use Stringable;
 
 interface NodeInterface extends Stringable
 {
-    public function parent(): null|NodeInterface;
+    public function parent(): null|ContainerInterface;
 
     public function setParent(
-        null|NodeInterface $parent
+        null|ContainerInterface $parent
     ): static;
 
-    public function document(): null|DocumentInterface;
+    public function parentTag(): null|TagInterface;
 
-    public function setDocument(
-        null|DocumentInterface $parent
-    ): static;
+    public function parentDocument(): null|DocumentInterface;
 
-    public function detach(): static;
+    /**
+     * @template T of NodeInterface
+     * @param class-string<T> $class
+     * @return null|T
+     */
+    public function parentOfType(string $class): mixed;
+
+    public function detachCopy(): static;
 }
diff --git a/src/Nodes/Comment.php b/src/Nodes/Comment.php
index 1e8b074..741a335 100644
--- a/src/Nodes/Comment.php
+++ b/src/Nodes/Comment.php
@@ -13,14 +13,25 @@ class Comment implements CommentInterface
     {
     }
 
+    public function value(): string
+    {
+        return $this->value;
+    }
+
+    public function setValue(string|Stringable $value): static
+    {
+        $this->value = $value;
+        return $this;
+    }
+
     public function __toString(): string
     {
         return sprintf(
             '<!-- %s -->',
             str_replace(
                 '--', // regular hyphens
-                '‑‑', // non-breaking hyphens
-                $this->value
+                '‑‑', // non-breaking hyphens, so they can't end the comment
+                $this->value()
             )
         );
     }
diff --git a/src/Nodes/CommentInterface.php b/src/Nodes/CommentInterface.php
index 0405dce..429919f 100644
--- a/src/Nodes/CommentInterface.php
+++ b/src/Nodes/CommentInterface.php
@@ -8,4 +8,6 @@ use Stringable;
 interface CommentInterface extends NodeInterface
 {
     public function __construct(Stringable|string $value);
+    public function value(): string;
+    public function setValue(string|Stringable $value): static;
 }
diff --git a/src/Nodes/Text.php b/src/Nodes/Text.php
index 0a1c87f..288aa3a 100644
--- a/src/Nodes/Text.php
+++ b/src/Nodes/Text.php
@@ -13,8 +13,19 @@ class Text implements TextInterface
     {
     }
 
+    public function value(): string
+    {
+        return $this->value;
+    }
+
+    public function setValue(string|Stringable $value): static
+    {
+        $this->value = $value;
+        return $this;
+    }
+
     public function __toString(): string
     {
-        return htmlentities(strip_tags($this->value));
+        return htmlentities(strip_tags($this->value()));
     }
 }
diff --git a/src/Nodes/TextInterface.php b/src/Nodes/TextInterface.php
index 0abf881..64da86f 100644
--- a/src/Nodes/TextInterface.php
+++ b/src/Nodes/TextInterface.php
@@ -8,4 +8,6 @@ use Stringable;
 interface TextInterface extends NodeInterface
 {
     public function __construct(Stringable|string $value);
+    public function value(): string;
+    public function setValue(string|Stringable $value): static;
 }
diff --git a/src/Nodes/UnsanitizedText.php b/src/Nodes/UnsanitizedText.php
index 6def807..7203d97 100644
--- a/src/Nodes/UnsanitizedText.php
+++ b/src/Nodes/UnsanitizedText.php
@@ -13,8 +13,19 @@ class UnsanitizedText implements TextInterface
     {
     }
 
-    public function __toString(): string
+    public function value(): string
     {
         return $this->value;
     }
+
+    public function setValue(string|Stringable $value): static
+    {
+        $this->value = $value;
+        return $this;
+    }
+
+    public function __toString(): string
+    {
+        return $this->value();
+    }
 }
diff --git a/src/Tags/AbstractContainerTag.php b/src/Tags/AbstractContainerTag.php
index baf60f1..7618f89 100644
--- a/src/Tags/AbstractContainerTag.php
+++ b/src/Tags/AbstractContainerTag.php
@@ -2,7 +2,6 @@
 
 namespace ByJoby\HTML\Tags;
 
-use ByJoby\HTML\Traits\ContainerMutableTrait;
 use ByJoby\HTML\Traits\ContainerTrait;
 use ByJoby\HTML\Traits\TagTrait;
 use ByJoby\HTML\Traits\NodeTrait;
@@ -10,7 +9,7 @@ use ByJoby\HTML\Traits\NodeTrait;
 abstract class AbstractContainerTag extends AbstractTag implements ContainerTagInterface
 {
     use NodeTrait, TagTrait;
-    use ContainerTrait, ContainerMutableTrait;
+    use ContainerTrait;
 
     public function __toString(): string
     {
diff --git a/src/Tags/AbstractGroupedTag.php b/src/Tags/AbstractGroupedTag.php
new file mode 100644
index 0000000..96e238b
--- /dev/null
+++ b/src/Tags/AbstractGroupedTag.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace ByJoby\HTML\Tags;
+
+abstract class AbstractGroupedTag extends AbstractContainerTag
+{
+}
diff --git a/src/Tags/ContainerTagInterface.php b/src/Tags/ContainerTagInterface.php
index 163998c..6d1af2f 100644
--- a/src/Tags/ContainerTagInterface.php
+++ b/src/Tags/ContainerTagInterface.php
@@ -2,7 +2,7 @@
 
 namespace ByJoby\HTML\Tags;
 
-use ByJoby\HTML\ContainerMutableInterface;
+use ByJoby\HTML\ContainerInterface;
 
 /**
  * Container Tags are HTML tags that are capable of holding a collection of
@@ -12,6 +12,6 @@ use ByJoby\HTML\ContainerMutableInterface;
  * 
  * @package ByJoby\HTML\Tags
  */
-interface ContainerTagInterface extends TagInterface, ContainerMutableInterface
+interface ContainerTagInterface extends TagInterface, ContainerInterface
 {
 }
diff --git a/src/Traits/ContainerMutableTrait.php b/src/Traits/ContainerMutableTrait.php
deleted file mode 100644
index 7a68836..0000000
--- a/src/Traits/ContainerMutableTrait.php
+++ /dev/null
@@ -1,103 +0,0 @@
-<?php
-
-namespace ByJoby\HTML\Traits;
-
-use ByJoby\HTML\Containers\DocumentInterface;
-use ByJoby\HTML\NodeInterface;
-use ByJoby\HTML\Nodes\Text;
-use ByJoby\HTML\Nodes\UnsanitizedText;
-use Exception;
-use Stringable;
-
-trait ContainerMutableTrait
-{
-    use ContainerTrait;
-
-    public function addChild(
-        NodeInterface|Stringable|string $child,
-        bool $prepend = false,
-        bool $skip_sanitize = false
-    ): static {
-        $child = $this->prepareChildToAdd($child, $skip_sanitize);
-        if ($prepend) array_unshift($this->children, $child);
-        else $this->children[] = $child;
-        return $this;
-    }
-
-    public function removeChild(
-        NodeInterface|Stringable|string $child
-    ): static {
-        $this->children = array_filter(
-            $this->children,
-            function (NodeInterface $e) use ($child) {
-                if (is_object($child)) return $e !== $child;
-                else return $e != $child;
-            }
-        );
-        return $this;
-    }
-
-    public function addChildBefore(
-        NodeInterface|Stringable|string $new_child,
-        NodeInterface|Stringable|string $before_child,
-        bool $skip_sanitize = false
-    ): static {
-        $i = $this->indexOfChild($before_child);
-        if ($i === null) {
-            throw new Exception('Reference child not found in this container');
-        }
-        $new_child = $this->prepareChildToAdd($new_child, $skip_sanitize);
-        array_splice($this->children, $i, 0, [$new_child]);
-        return $this;
-    }
-
-    public function addChildAfter(
-        NodeInterface|Stringable|string $new_child,
-        NodeInterface|Stringable|string $after_child,
-        bool $skip_sanitize = false
-    ): static {
-        $i = $this->indexOfChild($after_child);
-        if ($i === null) {
-            throw new Exception('Reference child not found in this container');
-        }
-        $new_child = $this->prepareChildToAdd($new_child, $skip_sanitize);
-        array_splice($this->children, $i + 1, 0, [$new_child]);
-        return $this;
-    }
-
-    protected function prepareChildToAdd(NodeInterface|Stringable|string $child, bool $skip_sanitize): NodeInterface
-    {
-        if (!($child instanceof NodeInterface)) {
-            if ($skip_sanitize) $child = new UnsanitizedText($child);
-            else $child = new Text($child);
-        }
-        if ($this instanceof NodeInterface) {
-            if ($child->parent() || $child->document()) {
-                $child->detach();
-            }
-            $child->setParent($this);
-            $child->setDocument($this->document());
-        }
-        if ($this instanceof DocumentInterface) {
-            if ($child->parent() || $child->document()) {
-                $child->detach();
-            }
-            $child->setDocument($this);
-        }
-        return $child;
-    }
-
-    protected function indexOfChild(NodeInterface|Stringable|string $child): null|int
-    {
-        if ($child instanceof NodeInterface) {
-            foreach ($this->children() as $i => $v) {
-                if ($v === $child) return $i;
-            }
-        } else {
-            foreach ($this->children() as $i => $v) {
-                if ($v == $child) return $i;
-            }
-        }
-        return null;
-    }
-}
diff --git a/src/Traits/ContainerTrait.php b/src/Traits/ContainerTrait.php
index ec81ba0..a5a8129 100644
--- a/src/Traits/ContainerTrait.php
+++ b/src/Traits/ContainerTrait.php
@@ -3,6 +3,10 @@
 namespace ByJoby\HTML\Traits;
 
 use ByJoby\HTML\NodeInterface;
+use ByJoby\HTML\Nodes\Text;
+use ByJoby\HTML\Nodes\UnsanitizedText;
+use Exception;
+use Stringable;
 
 trait ContainerTrait
 {
@@ -14,4 +18,89 @@ trait ContainerTrait
     {
         return $this->children;
     }
+
+    public function addChild(
+        NodeInterface|Stringable|string $child,
+        bool $prepend = false,
+        bool $skip_sanitize = false
+    ): static {
+        $child = $this->prepareChildToAdd($child, $skip_sanitize);
+        if ($prepend) array_unshift($this->children, $child);
+        else $this->children[] = $child;
+        return $this;
+    }
+
+    public function removeChild(
+        NodeInterface|Stringable|string $child
+    ): static {
+        $this->children = array_filter(
+            $this->children,
+            function (NodeInterface $e) use ($child) {
+                if (is_object($child)) $keep = $e !== $child;
+                else $keep = $e != $child;
+                if (!$keep) {
+                    $e->setParent(null);
+                }
+                return $keep;
+            }
+        );
+        return $this;
+    }
+
+    public function addChildBefore(
+        NodeInterface|Stringable|string $new_child,
+        NodeInterface|Stringable|string $before_child,
+        bool $skip_sanitize = false
+    ): static {
+        $i = $this->indexOfChild($before_child);
+        if ($i === null) {
+            throw new Exception('Reference child not found in this container');
+        }
+        $new_child = $this->prepareChildToAdd($new_child, $skip_sanitize);
+        array_splice($this->children, $i, 0, [$new_child]);
+        return $this;
+    }
+
+    public function addChildAfter(
+        NodeInterface|Stringable|string $new_child,
+        NodeInterface|Stringable|string $after_child,
+        bool $skip_sanitize = false
+    ): static {
+        $i = $this->indexOfChild($after_child);
+        if ($i === null) {
+            throw new Exception('Reference child not found in this container');
+        }
+        $new_child = $this->prepareChildToAdd($new_child, $skip_sanitize);
+        array_splice($this->children, $i + 1, 0, [$new_child]);
+        return $this;
+    }
+
+    protected function prepareChildToAdd(NodeInterface|Stringable|string $child, bool $skip_sanitize): NodeInterface
+    {
+        // turn strings into nodes
+        if (!($child instanceof NodeInterface)) {
+            if ($skip_sanitize) $child = new UnsanitizedText($child);
+            else $child = new Text($child);
+        }
+        // remove from parent, move it here, and return
+        if ($parent = $child->parent()) {
+            $parent->removeChild($child);
+        }
+        $child->setParent($this);
+        return $child;
+    }
+
+    protected function indexOfChild(NodeInterface|Stringable|string $child): null|int
+    {
+        if ($child instanceof NodeInterface) {
+            foreach ($this->children() as $i => $v) {
+                if ($v === $child) return $i;
+            }
+        } else {
+            foreach ($this->children() as $i => $v) {
+                if ($v == $child) return $i;
+            }
+        }
+        return null;
+    }
 }
diff --git a/src/Traits/NodeTrait.php b/src/Traits/NodeTrait.php
index f3d0ead..35fd34d 100644
--- a/src/Traits/NodeTrait.php
+++ b/src/Traits/NodeTrait.php
@@ -3,60 +3,47 @@
 namespace ByJoby\HTML\Traits;
 
 use ByJoby\HTML\ContainerInterface;
-use ByJoby\HTML\ContainerMutableInterface;
 use ByJoby\HTML\Containers\DocumentInterface;
 use ByJoby\HTML\NodeInterface;
+use ByJoby\HTML\Tags\TagInterface;
 use DeepCopy\DeepCopy;
-use Exception;
 
 trait NodeTrait
 {
-    /** @var null|NodeInterface */
+    /** @var null|ContainerInterface */
     protected $parent;
-    /** @var null|DocumentInterface */
-    protected $document;
 
     abstract function __toString();
 
-    public function parent(): null|NodeInterface
+    public function parent(): null|ContainerInterface
     {
         return $this->parent;
     }
 
-    public function setParent(null|NodeInterface $parent): static
+    public function setParent(null|ContainerInterface $parent): static
     {
         $this->parent = $parent;
         return $this;
     }
 
-    public function document(): null|DocumentInterface
+    public function parentTag(): null|TagInterface
     {
-        return $this->document;
+        return $this->parentOfType(TagInterface::class); // @phpstan-ignore-line
     }
 
-    public function setDocument(null|DocumentInterface $document): static
+    public function parentDocument(): null|DocumentInterface
     {
-        $this->document = $document;
-        if ($this instanceof ContainerInterface) {
-            foreach ($this->children() as $child) {
-                $child->setDocument($document);
-            }
-        }
-        return $this;
+        return $this->parentOfType(DocumentInterface::class); // @phpstan-ignore-line
     }
 
-    public function detach(): static
+    public function parentOfType(string $class): mixed
     {
-        $parent = $this->parent() ?? $this->document();
-        if ($parent === null) {
-            return $this;
-        } elseif ($parent instanceof ContainerMutableInterface) {
-            $parent->removeChild($this);
-            $this->setParent(null);
-            $this->setDocument(null);
-            return $this;
+        if ($this->parent() instanceof $class) {
+            return $this->parent();
+        } elseif ($this->parent() && $this->parent() instanceof NodeInterface) {
+            return $this->parent()->parentOfType($class);
         } else {
-            throw new Exception('Cannot detach() a Node from a parent that is not a ContainerMutableInterface, use detachCopy() instead');
+            return null;
         }
     }
 
@@ -65,7 +52,6 @@ trait NodeTrait
         static $copier;
         $copier = $copier ?? new DeepCopy();
         return ($copier->copy($this))
-            ->setParent(null)
-            ->setDocument(null);
+            ->setParent(null);
     }
 }
diff --git a/src/Traits/TagTrait.php b/src/Traits/TagTrait.php
index 5ba8e3e..a5371f7 100644
--- a/src/Traits/TagTrait.php
+++ b/src/Traits/TagTrait.php
@@ -64,7 +64,7 @@ trait TagTrait
 
     public function __toString(): string
     {
-        return sprintf('<%s/>', implode(' ', $this->openingTagStrings()));
+        return sprintf('<%s>', implode(' ', $this->openingTagStrings()));
     }
 
     /**
@@ -81,8 +81,11 @@ trait TagTrait
             $strings[] = sprintf('style="%s"', $this->styles());
         }
         foreach ($this->attributes() as $name => $value) {
-            if ($value === null) $strings[] = $name;
-            else $strings[] = sprintf('%s="%s"', $name, static::sanitizeAttribute($value));
+            if (is_string($value)) {
+                $strings[] = sprintf('%s="%s"', $name, static::sanitizeAttribute($value));
+            } elseif ($value) {
+                $strings[] = $name;
+            }
         }
         return $strings;
     }
diff --git a/tests/Containers/DocumentTags/HeadTagTest.php b/tests/Containers/DocumentTags/HeadTagTest.php
index 4645166..9a7e989 100644
--- a/tests/Containers/DocumentTags/HeadTagTest.php
+++ b/tests/Containers/DocumentTags/HeadTagTest.php
@@ -12,11 +12,4 @@ class HeadTagTest extends TestCase
         $this->assertInstanceOf(TitleTagInterface::class, $head->title());
         $this->assertEquals($head, $head->title()->parent());
     }
-
-    public function testNoTitleDetach()
-    {
-        $head = new HeadTag;
-        $this->expectExceptionMessage('Not allowed to detach TitleTag');
-        $head->title()->detach();
-    }
 }
diff --git a/tests/Containers/FragmentTest.php b/tests/Containers/FragmentTest.php
index 793a281..5f528f4 100644
--- a/tests/Containers/FragmentTest.php
+++ b/tests/Containers/FragmentTest.php
@@ -30,42 +30,17 @@ class FragmentTest extends TestCase
         $div2 = $this->tag('div');
         // adding div1 to fragment sets its fragment
         $fragment->addChild($div1);
-        $this->assertEquals($fragment, $div1->document());
+        $this->assertEquals($fragment, $div1->parentDocument());
         // adding div2 to div1 sets its document
         $div1->addChild($div2);
-        $this->assertEquals($fragment, $div2->document());
+        $this->assertEquals($fragment, $div2->parentDocument());
+        // div2's parent tag should be div1
+        $this->assertEquals($div1, $div2->parentTag());
+        // div1 should not have a parent tag
+        $this->assertNull($div1->parentTag());
         return $fragment;
     }
 
-    /** @depends clone testNestingDocument */
-    public function testDetaching(Fragment $fragment): void
-    {
-        /** @var AbstractContainerTag */
-        $div1 = $fragment->children()[0];
-        /** @var AbstractContainerTag */
-        $div2 = $div1->children()[0];
-        // add a span and verify it has the right parent
-        $span = $this->tag('span');
-        $div2->addChild($span);
-        $this->assertEquals($fragment, $span->document());
-        // detach and check document/parent of all nodes
-        $div1->detach();
-        $this->assertNull($div1->document());
-        $this->assertNull($div1->parent());
-        $this->assertNull($div2->document());
-        $this->assertEquals($div1, $div2->parent());
-        $this->assertNull($span->document());
-        $this->assertEquals($div2, $span->parent());
-        // try detaching again, to verify detaching a detached node does nothing
-        $div1->detach();
-        $this->assertNull($div1->document());
-        $this->assertNull($div1->parent());
-        $this->assertNull($div2->document());
-        $this->assertEquals($div1, $div2->parent());
-        $this->assertNull($span->document());
-        $this->assertEquals($div2, $span->parent());
-    }
-
     public function testMovingChild(): void
     {
         $fragment = new Fragment(['a', 'b']);
@@ -83,9 +58,9 @@ class FragmentTest extends TestCase
         $div2->addChild('a');
         // add child before a
         $div2->addChildBefore('b', 'a');
-        $this->assertEquals($fragment, $div2->children()[0]->document());
+        $this->assertEquals($fragment, $div2->children()[0]->parentDocument());
         // add child after a
         $div2->addChildAfter('c', 'a');
-        $this->assertEquals($fragment, $div2->children()[2]->document());
+        $this->assertEquals($fragment, $div2->children()[2]->parentDocument());
     }
 }
diff --git a/tests/Containers/GenericHtmlDocumentTest.php b/tests/Containers/GenericHtmlDocumentTest.php
index 75feb34..9c42210 100644
--- a/tests/Containers/GenericHtmlDocumentTest.php
+++ b/tests/Containers/GenericHtmlDocumentTest.php
@@ -22,10 +22,10 @@ class GenericHtmlDocumentTest extends TestCase
         $this->assertTrue($document->body() === $document->html()->body());
         $this->assertTrue($document->head() === $document->html()->head());
         // everything has the correct document
-        $this->assertEquals($document, $document->doctype()->document());
-        $this->assertEquals($document, $document->html()->document());
-        $this->assertEquals($document, $document->body()->document());
-        $this->assertEquals($document, $document->head()->document());
+        $this->assertEquals($document, $document->doctype()->parentDocument());
+        $this->assertEquals($document, $document->html()->parentDocument());
+        $this->assertEquals($document, $document->body()->parentDocument());
+        $this->assertEquals($document, $document->head()->parentDocument());
         // children are doctype and html
         $this->assertEquals([$document->doctype(), $document->html()], $document->children());
         // string version of an empty document
@@ -45,18 +45,4 @@ class GenericHtmlDocumentTest extends TestCase
             $document->__toString()
         );
     }
-
-    public function testNoDoctypeDetach(): void
-    {
-        $document = new GenericHtmlDocument;
-        $this->expectExceptionMessage('Cannot detach() a Node from a parent that is not a ContainerMutableInterface, use detachCopy() instead');
-        $document->doctype()->detach();
-    }
-
-    public function testNoHtmlDetach(): void
-    {
-        $document = new GenericHtmlDocument;
-        $this->expectExceptionMessage('Cannot detach() a Node from a parent that is not a ContainerMutableInterface, use detachCopy() instead');
-        $document->html()->detach();
-    }
 }
diff --git a/tests/Helpers/AttributesTest.php b/tests/Helpers/AttributesTest.php
index 1d218ea..6652d61 100644
--- a/tests/Helpers/AttributesTest.php
+++ b/tests/Helpers/AttributesTest.php
@@ -10,18 +10,18 @@ class AttributesTest extends TestCase
     {
         $attributes = new Attributes();
         $this->assertEquals([], $attributes->getArray());
-        $attributes = new Attributes(['foo' => 'bar', 'baz' => null]);
-        $this->assertEquals(['baz' => null, 'foo' => 'bar'], $attributes->getArray());
+        $attributes = new Attributes(['foo' => 'bar', 'baz' => true]);
+        $this->assertEquals(['baz' => true, 'foo' => 'bar'], $attributes->getArray());
         return $attributes;
     }
 
-    public function testInvalidConstructionEmptyName(): Attributes
+    public function testInvalidConstructionEmptyName(): void
     {
         $this->expectExceptionMessage('Attribute name must be specified when setting');
         $attributes = new Attributes(['' => 'foo']);
     }
 
-    public function testInvalidConstructionInvalidName(): Attributes
+    public function testInvalidConstructionInvalidName(): void
     {
         $this->expectExceptionMessage('Invalid character in attribute name');
         $attributes = new Attributes(['a=b' => 'foo']);
@@ -34,7 +34,7 @@ class AttributesTest extends TestCase
     {
         $attributes['a'] = 'b';
         $this->assertEquals('b', $attributes['a']);
-        $this->assertEquals(['a' => 'b', 'baz' => null, 'foo' => 'bar'], $attributes->getArray());
+        $this->assertEquals(['a' => 'b', 'baz' => true, 'foo' => 'bar'], $attributes->getArray());
         unset($attributes['baz']);
         $this->assertEquals(['a' => 'b', 'foo' => 'bar'], $attributes->getArray());
     }
@@ -44,9 +44,16 @@ class AttributesTest extends TestCase
      */
     public function testOffsetExists(Attributes $attributes): void
     {
+        // test with a regular string
         $this->assertFalse(isset($attributes['a']));
         $attributes['a'] = 'b';
         $this->assertTrue(isset($attributes['a']));
+        // test with an empty string
+        $attributes['b'] = '';
+        $this->assertTrue(isset($attributes['b']));
+        // test with a null value
+        $attributes['c'] = null;
+        $this->assertFalse(isset($attributes['c']));
     }
 
     /**
diff --git a/tests/Html5/Tags/ScriptTagTest.php b/tests/Html5/Tags/ScriptTagTest.php
new file mode 100644
index 0000000..0838378
--- /dev/null
+++ b/tests/Html5/Tags/ScriptTagTest.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace ByJoby\HTML\Html5\Tags;
+
+class ScriptTagTest extends TagTestCase
+{
+    public function testAttributeHelpers(): void
+    {
+        $this->assertAttributeHelperMethods('crossorigin', ScriptTag::class);
+        $this->assertAttributeHelperMethods('integrity', ScriptTag::class);
+        $this->assertAttributeHelperMethods('integrity', ScriptTag::class);
+        $this->assertAttributeHelperMethods('nonce', ScriptTag::class);
+        $this->assertAttributeHelperMethods('referrerpolicy', ScriptTag::class);
+        $this->assertAttributeHelperMethods('src', ScriptTag::class);
+        $this->assertAttributeHelperMethods('type', ScriptTag::class);
+        $this->assertBooleanAttributeHelperMethods('async', ScriptTag::class);
+        $this->assertBooleanAttributeHelperMethods('defer', ScriptTag::class);
+        $this->assertBooleanAttributeHelperMethods('nomodule', ScriptTag::class);
+    }
+}
diff --git a/tests/Html5/Tags/TagTestCase.php b/tests/Html5/Tags/TagTestCase.php
index 8365d6e..201503d 100644
--- a/tests/Html5/Tags/TagTestCase.php
+++ b/tests/Html5/Tags/TagTestCase.php
@@ -28,6 +28,23 @@ abstract class TagTestCase extends TestCase
         $this->assertNull(call_user_func([$tag, $getFn]));
     }
 
+    protected function assertBooleanAttributeHelperMethods(string $attribute, string $class): void
+    {
+        /** @var TagInterface */
+        $tag = new $class;
+        $words = explode('-', $attribute);
+        $setFn = 'set' . implode('', array_map('ucfirst', $words));
+        $getFn = array_shift($words) . implode('', array_map('ucfirst', $words));
+        // test setting true
+        call_user_func([$tag, $setFn], true);
+        $this->assertTagRendersBooleanAttribute($tag, $attribute, true);
+        $this->assertTrue(call_user_func([$tag, $getFn]));
+        // test setting false
+        call_user_func([$tag, $setFn], false);
+        $this->assertTagRendersBooleanAttribute($tag, $attribute, false);
+        $this->assertFalse(call_user_func([$tag, $getFn]));
+    }
+
     protected function assertTagRendersAttribute(TagInterface $tag, string $attribute, string $value)
     {
         if ($tag instanceof ContainerInterface || $tag instanceof ContentTagInterface) {
@@ -38,10 +55,43 @@ abstract class TagTestCase extends TestCase
             );
         } else {
             $this->assertEquals(
-                sprintf('<%s %s="%s"/>', $tag->tag(), $attribute, $value),
+                sprintf('<%s %s="%s">', $tag->tag(), $attribute, $value),
                 $tag->__toString(),
                 sprintf('Unexpected rendering of %s value %s is in %s tag', $attribute, $value, $tag->tag())
             );
         }
     }
+
+    protected function assertTagRendersBooleanAttribute(TagInterface $tag, string $attribute, bool $value)
+    {
+        if ($tag instanceof ContainerInterface || $tag instanceof ContentTagInterface) {
+            if ($value) {
+                $this->assertEquals(
+                    sprintf('<%s %s></%s>', $tag->tag(), $attribute, $tag->tag()),
+                    $tag->__toString(),
+                    sprintf('Unexpected rendering of %s value %s is in %s tag', $attribute, $value ? 'true' : 'false', $tag->tag())
+                );
+            } else {
+                $this->assertEquals(
+                    sprintf('<%s></%s>', $tag->tag(), $tag->tag()),
+                    $tag->__toString(),
+                    sprintf('Unexpected rendering of %s value %s is in %s tag', $attribute, $value ? 'true' : 'false', $tag->tag())
+                );
+            }
+        } else {
+            if ($value) {
+                $this->assertEquals(
+                    sprintf('<%s %s>', $tag->tag(), $attribute),
+                    $tag->__toString(),
+                    sprintf('Unexpected rendering of %s value %s is in %s tag', $attribute, $value ? 'true' : 'false', $tag->tag())
+                );
+            } else {
+                $this->assertEquals(
+                    sprintf('<%s>', $tag->tag()),
+                    $tag->__toString(),
+                    sprintf('Unexpected rendering of %s value %s is in %s tag', $attribute, $value ? 'true' : 'false', $tag->tag())
+                );
+            }
+        }
+    }
 }
diff --git a/tests/Nodes/CommentTest.php b/tests/Nodes/CommentTest.php
index ba34766..2208966 100644
--- a/tests/Nodes/CommentTest.php
+++ b/tests/Nodes/CommentTest.php
@@ -13,4 +13,12 @@ class CommentTest extends TestCase
         $this->assertEquals('<!-- foo-bar -->', new Comment('foo-bar'));
         $this->assertNotEquals('<!-- foo--bar -->', new Comment('foo--bar'));
     }
+
+    public function testModification(): void
+    {
+        $comment = new Comment('foo');
+        $this->assertEquals('foo', $comment->value());
+        $comment->setValue('bar');
+        $this->assertEquals('bar', $comment->value());
+    }
 }
diff --git a/tests/Nodes/TextTest.php b/tests/Nodes/TextTest.php
index af80b09..ccde882 100644
--- a/tests/Nodes/TextTest.php
+++ b/tests/Nodes/TextTest.php
@@ -12,4 +12,12 @@ class TextTest extends TestCase
         $this->assertEquals('foo', new Text('foo'));
         $this->assertEquals('foo', new Text('<strong>foo</strong>'));
     }
+
+    public function testModification(): void
+    {
+        $text = new Text('foo');
+        $this->assertEquals('foo', $text->value());
+        $text->setValue('bar');
+        $this->assertEquals('bar', $text->value());
+    }
 }
diff --git a/tests/Nodes/UnsanitizedTextTest.php b/tests/Nodes/UnsanitizedTextTest.php
index dd4555c..0e67072 100644
--- a/tests/Nodes/UnsanitizedTextTest.php
+++ b/tests/Nodes/UnsanitizedTextTest.php
@@ -12,4 +12,12 @@ class UnsanitizedTextTest extends TestCase
         $this->assertEquals('foo', new UnsanitizedText('foo'));
         $this->assertEquals('<strong>foo</strong>', new UnsanitizedText('<strong>foo</strong>'));
     }
+
+    public function testModification(): void
+    {
+        $text = new UnsanitizedText('foo');
+        $this->assertEquals('foo', $text->value());
+        $text->setValue('bar');
+        $this->assertEquals('bar', $text->value());
+    }
 }
diff --git a/tests/Tags/AbstractContainerTagTest.php b/tests/Tags/AbstractContainerTagTest.php
index f797b1c..8274ff7 100644
--- a/tests/Tags/AbstractContainerTagTest.php
+++ b/tests/Tags/AbstractContainerTagTest.php
@@ -34,6 +34,15 @@ class AbstractContainerTagTest extends TestCase
         return $div;
     }
 
+    public function testBooleanAttributes(): void
+    {
+        $tag = $this->tag('div');
+        $tag->attributes()['a'] = true;
+        $tag->attributes()['b'] = false;
+        $tag->attributes()['c'] = null;
+        $this->assertEquals('<div a></div>', $tag->__toString());
+    }
+
     /** @depends clone testDIV */
     public function testMoreNesting(AbstractContainerTag $div): AbstractContainerTag
     {
@@ -79,16 +88,6 @@ class AbstractContainerTagTest extends TestCase
         $this->assertInstanceOf(UnsanitizedText::class, $div->children()[2]);
     }
 
-    /** @depends clone testMoreNesting */
-    public function testDetach(AbstractContainerTag $div): void
-    {
-        /** @var AbstractContainerTag */
-        $span = $div->children()[0];
-        $span->detach();
-        $this->assertEquals('<div a="b"></div>', $div->__toString());
-        $this->assertNull($span->parent());
-    }
-
     /** @depends clone testMoreNesting */
     public function testDetachCopy(AbstractContainerTag $div): void
     {
diff --git a/tests/Tags/AbstractTagTest.php b/tests/Tags/AbstractTagTest.php
index b6b1920..f799827 100644
--- a/tests/Tags/AbstractTagTest.php
+++ b/tests/Tags/AbstractTagTest.php
@@ -19,7 +19,7 @@ class AbstractTagTest extends TestCase
     public function testBR(): AbstractTag
     {
         $br = $this->tag('br');
-        $this->assertEquals('<br/>', $br->__toString());
+        $this->assertEquals('<br>', $br->__toString());
         $this->assertInstanceOf(Classes::class, $br->classes());
         $this->assertInstanceOf(Attributes::class, $br->attributes());
         return $br;
@@ -33,10 +33,10 @@ class AbstractTagTest extends TestCase
         $this->assertNull($tag->id());
         $tag->setID('foo');
         $this->assertEquals('foo', $tag->id());
-        $this->assertEquals('<br id="foo"/>', $tag->__toString());
+        $this->assertEquals('<br id="foo">', $tag->__toString());
         $tag->setID(null);
         $this->assertNull($tag->id());
-        $this->assertEquals('<br/>', $tag->__toString());
+        $this->assertEquals('<br>', $tag->__toString());
     }
 
     /**
@@ -46,12 +46,21 @@ class AbstractTagTest extends TestCase
     {
         $tag->attributes()['b'] = 'c';
         $tag->attributes()['a'] = 'b';
-        $this->assertEquals('<br a="b" b="c"/>', $tag->__toString());
+        $this->assertEquals('<br a="b" b="c">', $tag->__toString());
         unset($tag->attributes()['a']);
-        $this->assertEquals('<br b="c"/>', $tag->__toString());
+        $this->assertEquals('<br b="c">', $tag->__toString());
         $tag->classes()->add('some-class');
         $tag->styles()['style'] = 'value';
-        $this->assertEquals('<br class="some-class" style="style:value" b="c"/>', $tag->__toString());
+        $this->assertEquals('<br class="some-class" style="style:value" b="c">', $tag->__toString());
+    }
+
+    public function testBooleanAttributes(): void
+    {
+        $tag = $this->tag('br');
+        $tag->attributes()['a'] = true;
+        $tag->attributes()['b'] = false;
+        $tag->attributes()['c'] = null;
+        $this->assertEquals('<br a>', $tag->__toString());
     }
 
     /**