Securitypopular
Basic XSS Detection Regex Pattern
Detects common XSS patterns.
Pattern
<script[^>]*>.*?<\/script>|javascript:|onerror=|onload=Tested examples
<script>alert('XSS')</script>javascript:alert(1)normal text<div>content</div>Test it live
Live Regex TesterJS
2 matches/
/g
<script>alert('XSS')</script>
javascript:alert(1)Match 1at index 0
<script>alert('XSS')</script>Match 2at index 30
javascript:Use it in your language
Use it in
// JavaScript / Node.js
const regex = /<script[^>]*>.*?<\/script>|javascript:|onerror=|onload=/;
const value = "<script>alert('XSS')</script>";
const isMatch = regex.test(value);
console.log(isMatch); // true / false
// Extract all matches
const matches = value.match(/<script[^>]*>.*?<\/script>|javascript:|onerror=|onload=/g) || [];Tags
Frequently asked questions
How do I use the Basic XSS Detection regex pattern in JavaScript?
Wrap the pattern in slashes: const re = /<script[^>]*>.*?<\/script>|javascript:|onerror=|onload=/; — then call re.test(value) to check a single value, or value.match(re) to find matches. The "Use it in" snippets above give you the exact code for 9 languages.
Is this basic xss detection regex production-ready?
Yes — every pattern in the library is tested against valid and invalid examples. Still, regex is one layer in a defense-in-depth strategy: pair it with server-side validation (e.g. Luhn for credit cards, mod-97 for IBAN, real DNS lookup for emails) for critical inputs.
Why does my pattern fail in another language?
Different regex engines (PCRE, Java, Python, Go's RE2) support slightly different syntax. The most common gotchas: lookbehinds (not in RE2), named groups syntax, and how backslashes need to be escaped inside string literals. The code snippets above already escape correctly for each language.
Can I edit this pattern and test it live?
Yes — use the live tester above. Type your test string and toggle flags (g, i, m, s, u, y) to see matches highlighted instantly, including capture groups.
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