The targets differ: URL encoding turns characters into %XX byte sequences so content can travel safely in a URL; HTML entities turn characters into &name; or &#nnn; so content can enter HTML text safely. Using the wrong one for the container does nothing useful and can double-encode.
| URL Encode / Decode | HTML Entity Encode / Decode | |
|---|---|---|
| Output shape | Percent sequences like %E4%B8%AD | Entities like &, ©, ' |
| Container | URL query strings and paths | HTML / XML text and attribute values |
| Who decodes | Browsers and servers, by URL rules | The HTML parser, while rendering |
| Classic mistake | Re-encoding an encoded string: % becomes %25 | Putting entities in a URL, where nothing decodes them |
URL (percent) encoding turns special characters into %XX form so the URL transmits safely. Encode: escapes with encodeURIComponent Decode: restores with decodeURIComponent Letters, digits and the safe characters -_.!~*'() are preserved
HTML entity encoding turns special characters into safe entity references. Encode: turns < > & " into entities Decode: turn entities back into characters Covers 37 common HTML entities
Decide by container: percent-encoding for URLs, entities for HTML. When both apply the order is URL-encode first, then HTML-escape the result — the reverse leaves entities that never decode.
