Regex for HTML Tags

Matching HTML with Regular Expressions

Regex and HTML have a famously complicated relationship. Every developer eventually needs to strip tags, extract a link, or grep for a specific element — and regex looks like the fastest tool for the job. It often is. But regex fundamentally cannot parse HTML correctly in all cases because HTML is a nested language and regex has no memory of nesting. This guide covers what regex CAN do reliably, what patterns to use, and when to switch to a proper parser.

The Core Patterns

Match any HTML tag

/<[^>]+>/g       // opens with <, closes with >, no > in between
/<\/?[a-z][a-z0-9]*\b[^>]*>/gi   // stricter — must start with a letter

The stricter pattern refuses to match nonsense like <123> or bare <>. It also handles closing tags via the optional \/?.

Match a specific tag with content

// <p>...anything...</p>  — the [\s\S]*? is a "match anything lazily" trick
/<p[^>]*>([\s\S]*?)<\/p>/gi

// <a> tag with its href
/<a\s[^>]*href\s*=\s*["']([^"']+)["'][^>]*>([\s\S]*?)<\/a>/gi

// <img> tag with its src (self-closing, no closing tag)
/<img\s[^>]*src\s*=\s*["']([^"']+)["'][^>]*\/?>/gi

Extract just the tag name

/<([a-z][a-z0-9]*)\b/gi  // captures p, div, span, h1, etc.

Strip all attributes but keep the tag

// Turns <p class="foo" id="bar">text</p> into <p>text</p>
html.replace(/<([a-z][a-z0-9]*)\b[^>]*>/gi, '<$1>');

Language-Specific Usage

JavaScript — strip all HTML tags

function stripHtml(html) {
  return html
    .replace(/<[^>]+>/g, '')      // remove tags
    .replace(/&nbsp;/g, ' ')      // decode common entities
    .replace(/&amp;/g,  '&')
    .replace(/&lt;/g,   '<')
    .replace(/&gt;/g,   '>')
    .replace(/&quot;/g, '"')
    .replace(/\s+/g, ' ')        // collapse whitespace
    .trim();
}

stripHtml('<p class="foo">Hello <b>world</b>!</p>');
// → 'Hello world!'

// SAFER alternative — use the DOM
function stripHtmlSafe(html) {
  const doc = new DOMParser().parseFromString(html, 'text/html');
  return doc.body.textContent || '';
}

Python

import re

TAG_RE = re.compile(r'<[^>]+>')

def strip_html(html: str) -> str:
    return re.sub(TAG_RE, '', html)

# Better — use BeautifulSoup for anything non-trivial
from bs4 import BeautifulSoup

def strip_html_safe(html: str) -> str:
    return BeautifulSoup(html, 'html.parser').get_text(' ', strip=True)

PHP

// PHP has a purpose-built function — use it
$plain = strip_tags($html);

// Allow certain tags through
$plain = strip_tags($html, '<b><i><a>');

// Or regex if you need custom logic
$plain = preg_replace('/<[^>]+>/', '', $html);

When Regex Fails

Quoted > inside attributes

The pattern <[^>]+> stops at the first >. But this is valid HTML:

<a title="1 > 0">click</a>

The regex matches <a title="1 > and stops — cutting the tag in half. A stricter pattern that handles quoted strings exists but is much longer:/<[a-z][^>"]*(?:"[^"]*"[^>"]*)*>/gi.

Comments and CDATA

HTML comments <!-- ... --> and CDATA blocks are matched by generic tag patterns, which almost never what you want. Always strip them first:

html
  .replace(/<!--[\s\S]*?-->/g, '')     // strip comments
  .replace(/<!\[CDATA\[[\s\S]*?\]\]>/g, '');  // strip CDATA

Nested tags of the same type

Regex cannot correctly match nested <div><div></div></div> because it has no way to track depth. The lazy match ([\s\S]*?) stops at the first closing tag, cutting nested structures in half. This is the classic case for switching to a DOM parser.

Script and style content

<script> and <style> contents can contain characters that look like HTML tags but are not. Regex will happily match them, which is almost certainly wrong. Strip these blocks first:

html
  .replace(/<script[\s\S]*?<\/script>/gi, '')
  .replace(/<style[\s\S]*?<\/style>/gi, '');

HTML Regex Cheatsheet

Testing Your HTML Regex

Use the live Regex Tester with these HTML snippets:

• Simple: <p>hello</p>
• With attributes: <a href="/x" class="btn">click</a>
• Self-closing: <br/>, <img src="x.png"/>
• Nested: <div><p><strong>bold</strong></p></div>
• Trap: > in attribute: <a title="1 > 0">x</a>
• Comment: <!-- do not match this -->

Related Tools

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• Find & Replace Tool
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