About

Converting raw HTML strings into rendered DOM views is a routine operation in front-end development, yet malformed markup silently breaks layouts and introduces cross-browser inconsistencies. A missing closing tag or an unescaped & entity can cascade into rendering failures that are invisible in source code. This tool parses your input string through the browser's native DOMParser API, detects structural errors at the token level, and renders the result in a sandboxed frame. It reports node counts, tree depth, and element distribution. The parser operates on the same engine your browser uses, so the output matches production behavior exactly. Note: inline <script> tags are stripped for security. Self-closing tag handling follows the HTML5 specification, not XHTML rules.

Formulas

The conversion pipeline follows a deterministic three-stage process. The input string S is first tokenized, then parsed into a DOM tree T, and finally rendered into a sandboxed view V.

V = render(parse(tokenize(S)))

The parser uses the browser-native DOMParser which implements the HTML5 parsing algorithm. Error detection checks for the presence of parsererror nodes in the resulting document. Node statistics are computed by a recursive tree walk.

depth(node) = 1 + max(depth(child_i))

Where S is the raw input string. T is the parsed DOM tree. V is the rendered visual output. depth computes the maximum nesting level recursively across all child branches. tokenize splits the string into tag tokens, attribute tokens, text nodes, and comment nodes using a finite-state lexer. The total node count N = elements + text nodes + comments.

Reference Data

HTML Entity	Character	Code Point	Usage Context
`&`	&	U+0026	Ampersand in text content
`<`	<	U+003C	Less-than in text content
`>`	>	U+003E	Greater-than in text content
`"`	"	U+0022	Double quote in attributes
`'`	'	U+0027	Single quote (XML/XHTML)
	(non-breaking space)	U+00A0	Prevent word wrapping
`©`	©	U+00A9	Copyright symbol
`®`	®	U+00AE	Registered trademark
`™`	™	U+2122	Trademark symbol
`—`	-	U+2014	Em dash in prose
`–`	-	U+2013	En dash for ranges
`«`	«	U+00AB	Left guillemet
`»`	»	U+00BB	Right guillemet
`…`	…	U+2026	Horizontal ellipsis
`•`	•	U+2022	Bullet point
`←`	←	U+2190	Left arrow
`→`	→	U+2192	Right arrow
	(line feed)	U+000A	Newline in attribute values
	(tab)	U+0009	Tab in preformatted content
`☃`	☃	U+2603	Numeric hex entity example

Frequently Asked Questions

The tool uses the HTML5 parsing algorithm via DOMParser with "text/html" mode. In HTML5, void elements (br, hr, img, input, meta, link, etc.) are self-closing by definition. Writing
or
produces identical DOM nodes. However, non-void elements written as self-closing (e.g.,

) will NOT self-close - the parser treats them as opening tags, which may cascade into unexpected nesting.

Script tags are intentionally stripped during rendering for security. Executing arbitrary JavaScript from string input would create XSS (Cross-Site Scripting) vulnerabilities. The tool focuses on visual DOM rendering, not script execution. If you need to test scripts, use your browser's developer console.

The HTML5 parser enforces implicit closing rules. A

element cannot contain block-level elements. When the parser encounters

...

, it implicitly closes the

before the

, resulting in two sibling elements: an empty

and a

. The tool's node tree will reflect this corrected structure, not your original intent. Check the node count - if it differs from expected, invalid nesting is likely the cause.

By default, HTML collapses consecutive whitespace into a single space during rendering. The preview matches this browser behavior. If you need preserved whitespace, wrap content in

 tags or apply CSS white-space: pre to the relevant elements. The syntax-highlighted source view shows your original whitespace unchanged.

The tool supports ${...} placeholder syntax for demonstration purposes. Variables are detected and highlighted in the source view, but since no JavaScript execution context exists, they render as literal text in the preview. This helps you validate template structure before integrating with a framework like Strve.js or lit-html.

The tool processes inputs up to approximately 500KB of HTML string content without significant delay. Beyond that, the DOMParser and syntax highlighter may introduce latency above 200ms. For very large documents (over 1MB), parsing is deferred with a loading indicator. The practical limit is your browser's memory - typically several megabytes of DOM content before tab performance degrades.