AnyTools
📄
HTML Formatter
Format and beautify HTML code with professional indentation, syntax highlighting, and minification. Support code validation and quick operations.
Indent Size:
2
Input HTML
Formatted Output
❓What is HTML Formatter
HTML formatter tool for formatting and beautifying HTML code with proper indentation, syntax validation, and structure optimization.
✨Features
🎨
Smart Formatting
Professional HTML beautification with customizable indentation (2/4 spaces), line breaks, and tag alignment using js-beautify library
🗜️
One-Click Minification
Remove whitespace, comments, and line breaks to compress HTML file size for production deployment
💻
Syntax Highlighting
CodeMirror editor with HTML syntax highlighting, line numbers, code folding, and tag matching
🔄
Quick Operations
Load sample HTML, swap input/output, copy results, and toggle dark theme for efficient workflow
📋Best Practices
Clean before formatting
Remove dead code, empty tags and extra whitespace to reduce meaningless diffs.
Follow team rules
Keep indent, quotes and attribute order aligned with project Prettier/HTMLHint.
Handle inline code carefully
Use dedicated JS/CSS formatters for <script> and <style> blocks if needed.
Mind accessibility
Check heading hierarchy, aria-* and semantic tags after formatting.
Validate before deploy
Run W3C Validator/Lighthouse to ensure valid and stable output.
📚Technical Introduction
🏗️HTML DOM Structure Parsing
HTML (HyperText Markup Language) formatter uses DOM (Document Object Model) parser to analyze HTML structure. HTML documents consist of Elements, Attributes, and Text Nodes forming a tree structure. Parsing flow: tokenization identifies tags, attributes, text → parsing builds DOM tree → validates tag nesting and closure → handles self-closing tags (<img/>, <br/>). Supports HTML5 features, error-tolerant parsing (auto-fix tags), preserving comments and CDATA.
📐HTML Formatting and Beautification Rules
HTML formatting includes: indentation management (increase indent per nesting level), tag line breaks (block elements on separate lines, inline elements stay inline), attribute alignment (multi-line attribute alignment), whitespace handling (between tags and content), quote uniformity (single or double quotes). Special handling: <pre>, <code>, <script>, <style> tag content preserved as-is, SVG embedded code formatting, Web Components support. Beautified HTML improves readability, facilitates code review, debugging and maintenance.
⚡HTML Minification and Performance Optimization
HTML minification techniques: remove whitespace and line breaks, remove comments, compress inline CSS and JavaScript, simplify boolean attributes (checked="checked" → checked), remove optional closing tags, reducing file size by 20-40%. Advanced optimization: critical CSS extraction, resource preload hints (preload, prefetch), image lazy loading attributes. Tool supports both beautification and minification modes, suitable for development (readability priority) and production (performance priority) environments, improving page load speed and user experience.
❓
FAQ
❓
Will formatting remove my HTML comments?
Beautify keeps comments; Minify usually removes them to reduce file size.
💬
How are inline <script> and <style> handled?
Contents are kept as-is by default. For deep optimization, use dedicated JS/CSS formatters.
🔍
Does it follow HTML5 spec?
It respects HTML5 tolerance and closing rules; still validate with W3C Validator.
💡
Can I enforce double quotes for attributes?
Choose a unified quote style before formatting to normalize attributes.
📚
Is my code uploaded to a server?
No. Everything runs locally in your browser and clears when you close the page.
💡How To & Tips
📝
Paste Your Code
Copy and paste your code into the input editor. The tool automatically detects the code structure and prepares it for formatting.
⚙️
Customize Format Settings
Adjust formatting options like indentation size, line width, quote style, and semicolon usage. Preview changes in real-time as you modify settings.
✨
Format and Review
Click the format button to beautify your code. The tool applies professional formatting standards, improves readability, and highlights syntax automatically.
📋
Copy Formatted Code
Copy the formatted code to your clipboard with one click. The code maintains proper indentation and structure for direct use in your projects.
🔗Related Documents
📝Update Log
📌v1.11.251025v1.11.251025Upgraded to CodeMirror editor with syntax highlighting; Added HTML beautification (js-beautify) and minification; Added indent size options (2/4 spaces), dark theme, load sample, and swap buttons; Fixed responsive layout; Optimized content quality and internationalization(2025-10-25)
User Comments
Loading...