About

In the architecture of the web, HTML (HyperText Markup Language) serves as the foundational skeleton. However, as applications grow in complexity, the nesting of elements - the Document Object Model (DOM) - can become unwieldy, leading to rendering performance bottlenecks and accessibility failures. A raw string of code often obscures these structural flaws.

This tool is engineered to bridge the gap between raw syntax and structural reality. By parsing the input string into a traversable node tree, it exposes the depth of nesting, identifies deprecated entities, and visualizes the parent-child relationships that dictate layout behavior. It is designed for developers who require a granular inspection of their markup without the overhead of a full browser Developer Tools environment.

Formulas

The DOM Complexity Score (S_c) is a heuristic estimation of rendering cost, derived from total nodes (N), maximum nesting depth (D), and the count of heavy script/media elements (H).

S_c ≈ N + (D × 5) + (H × 20)

Where H is the sum of <script>, <iframe>, and <embed> tags. A score > 1500 often indicates a need for refactoring.

Reference Data

Tag Name	Category	Display Behavior	Semantic Purpose
`<html>`	Root	Block	Root element of an HTML document.
`<head>`	Metadata	None	Container for metadata (title, scripts, styles).
`<body>`	Sectioning	Block	Contains all the visible content of the document.
`<div>`	Flow Content	Block	Generic container for flow content.
`<span>`	Phrasing	Inline	Generic inline container for phrasing content.
`<a>`	Interactive	Inline	Hyperlink to other web pages or locations.
`<img>`	Embedded	Inline-block	Embeds an image into the document.
`<p>`	Flow Content	Block	Represents a paragraph.
`<ul>`	Flow Content	Block	Unordered list (bullet points).
`<ol>`	Flow Content	Block	Ordered list (numbered).
`<li>`	Flow Content	List-item	Represents an item in a list.
`<table>`	Tabular	Table	Represents tabular data.
`<tr>`	Tabular	Table-row	Defines a row in a table.
`<td>`	Tabular	Table-cell	Defines a cell in a table.
`<form>`	Interactive	Block	Represents a document section for interactive controls.
`<input>`	Interactive	Inline-block	Input field for user data.
`<button>`	Interactive	Inline-block	Clickable button.
`<script>`	Metadata	None	Embeds or references executable code.
`<style>`	Metadata	None	Contains styling information.
`<meta>`	Metadata	None	Metadata about the HTML document.
`<link>`	Metadata	None	Specifies relationships between documents.
`<header>`	Sectioning	Block	Introductory content or navigational aids.
`<footer>`	Sectioning	Block	Footer for a section or page.
`<nav>`	Sectioning	Block	Section with navigation links.
`<article>`	Sectioning	Block	Self-contained composition.
`<section>`	Sectioning	Block	Generic section of a document.
`<aside>`	Sectioning	Block	Content tangentially related to the main content.
`<main>`	Sectioning	Block	Dominant content of the <body>.
`<canvas>`	Embedded	Inline-block	Graphics drawing via scripting (JS).
`<video>`	Embedded	Inline-block	Embeds video content.

Frequently Asked Questions

Syntax Highlighting colorizes the raw text code to make it readable (tags vs attributes). The Tree View actually parses the code into a DOM (Document Object Model) structure, showing the parent-child hierarchy. The Tree View reveals "invisible" structure, such as how the browser automatically closes unclosed tags.

Empty tags (like ) often accumulate during WYSIWYG editing or sloppy coding. They add no semantic value but increase the DOM size, which takes up memory and processing power. Cleaning them improves page performance.

The Preview runs inside a sandboxed iframe. While basic scripts may execute, the sandbox attribute restricts actions like popups, top-navigation, and form submission to ensure security.

This metric scans for common WCAG failures, such as images missing "alt" attributes, form inputs missing labels, or button elements without text content. These omissions make the HTML unusable for screen readers.