ConverterURL Encoding vs HTML Character References
Choose percent encoding for a URL component or form value and HTML character references for an HTML context without confusing representation with sanitization.
Need To Check A Conversion?
Use the URL Encode tool for the direct action. This guide stays focused on the explanation, tradeoffs, mistakes, and reference context behind that task.
Choose By Destination
| Destination | Representation | Important distinction |
|---|---|---|
| One URI component | UTF-8 percent encoding | A complete URL has separate components |
| Form value | application/x-www-form-urlencoded | Space becomes + |
| HTML text or quoted attribute | HTML character references as needed | Context and safe sink still matter |
| JavaScript or CSS | Language-specific escaping | Neither URL nor HTML encoding is a universal substitute |
Plus And Percent Are Not Universal Rules
A literal plus remains plus in URI-component decoding, while a form decoder maps it to a space. A literal plus in form data must be encoded as %2B.
Decode one layer by default. Recursive decoding can turn literal percent sequences into new syntax and hide double-encoding defects.
Encoding Is Not Sanitization
Percent encoding does not make a redirect destination trustworthy. HTML character references do not sanitize arbitrary markup or make every DOM sink safe.
Validate values and choose a safe output API after decoding. Keep the original representation when troubleshooting.
Related Tools
References
- WHATWG URL Standard - Primary URL parsing and application/x-www-form-urlencoded algorithms.
- WHATWG HTML Standard - Character References - Primary HTML named character-reference definitions.
- OWASP Cross Site Scripting Prevention Cheat Sheet - Context-sensitive output encoding and safe-sink guidance.
Related Guides In This Category
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