HTML Formatter

HTML Formatter

Format, indent, and organize HTML code snippets and templates locally inside your web browser. Built with client-side DOM parsing engines, this utility formats your markup code in memory, ensuring that template designs, logs, or corporate layouts are never sent to remote servers.

Language Specifications & Standards

• World Wide Web Consortium (W3C): HTML5 Living Standard Specification.
• WHATWG: Web Hypertext Application Technology Working Group HTML Specification.
• Unicode Consortium: Standard Guidelines for Hex Representation.

HTML Formatter Online — Code Beautifier & Indenter

This utility takes unformatted, minified, or disorganized HTML blocks and cleans their structure. It formats nested tags with consistent indentation (2 spaces, 4 spaces, or tabs), wraps long lines, aligns opening and closing tags, and validates code to prevent structural nesting errors.

HTML formatting uses parser trees to analyze and reconstruct element arrangements:

1. 1DOM Parsing:

The browser converts the raw input string into a structured Document Object Model (DOM) tree.

• Elements, text blocks, and comment strings are converted into tree nodes.
• Self-closing tags (like <img>, <input>, or <br>) are identified to prevent structural errors.

1. 2Recursive Formatting:

The formatter recursively walks the nodes, applying rules:

• Nesting Indentation: Inserts tabs or spaces before nodes based on their nesting depth.
• Attribute Wrapping: Formats long lists of attributes to fit maximum line widths.
• Whitespace Cleaning: Strips double spaces and trailing newlines from text nodes.

1. 3Time Complexity:

DOM parsing and tree generation operate in linear time:

Time Complexity = O(N)

Where N is the number of code tokens. This guarantees fast performance for standard pages.

[Unformatted HTML String]
          |
          v
[DOM Parser Token Tree Setup]
          |
          v
[Identify Tag Types: Standard, Self-Closing, or Text Node]
          |
          v
[Apply Recursive Nesting Indentation & Line Wrapping Rules]
          |
          v
[Output Formatted HTML Code]

• Formatted Output Looks Broken: Check if your input contains invalid template tags (like PHP or handlebars templates) that confuse the HTML parser.
• Indentation Seems Inconsistent: Verify if your text has mixed tab and space formatting in its original structure. Try run-cleaning spacing before formatting.
• Results Aren't Loading: Ensure JavaScript is enabled in your browser settings.

Why does the formatter change template codes?

Because standard HTML formatters parse code using standard DOM engines. If your code contains non-HTML syntax (like Angular, React, or PHP tags), the parser tries to interpret them as standard elements, which can corrupt the output.

What are self-closing tags?

Self-closing tags (like <br>, <img>, <hr>, or <meta>) do not require a separate closing tag (</tag>). The formatter recognizes these according to HTML5 standards to prevent formatting errors.

Are my web templates logged?

No. All formatting operations run locally on your device within your web browser sandbox.

• JSON Formatter: Format, beautify, and validate JSON data inputs, generating collapsible interactive tree node views.
• JSON Validator: Validate JSON structures and locate specific syntax errors.
• JSON Compare: Compare two JSON documents and identify added, removed, changed, or mismatched paths.
• JSON Minifier: Compress JSON files by removing spacing and indentation properties.
• Base64 Encoder: Convert string variables and binary assets to standard Base64 format.
• Base64 Decoder: Convert Base64 formatted string blocks back to standard readable text.

Before & After Code Example

• Minified Input: <div><p>Hello <b>World</b></p></div>
• Formatted Output (2 Spaces):

<div>
  <p>Hello <b>World</b></p>
</div>

• Attribute Realignment: Formats multiple class names to fit cleaner column blocks.

• Use 2 Spaces for Production Code: Keep templates compact and easy to read by using standard 2-space indentation.
• Clean Comments Before Delivery: Strip unnecessary build comments from HTML templates before publishing.
• Verify Tag Closures: Use the visual alignment of closing tags to cross-check structural consistency.