Media type · text/javascript
text/javascript
text/javascript is the standard media type for JavaScript source files.
Key facts
| Type | text/javascript |
|---|---|
| Extensions | .js, .mjs |
| Standard | RFC 9239 |
| Text or binary | Text |
| Legacy type | application/javascript |
What text/javascript is
RFC 9239 makes text/javascript the preferred media type for JavaScript. It is used for classic scripts, modules and JavaScript served to browsers. application/javascript is obsolete but still accepted by browsers for compatibility.
MIME checking and modules
Module scripts (type="module") are subject to strict MIME checking: a module served as text/plain is rejected. With X-Content-Type-Options: nosniff, classic scripts are checked too. This is a security feature: it stops a server from letting an uploaded text file execute as script. If a script works when pasted inline but fails when loaded from a file, the response type is the first thing to check.
Frequently asked questions
Should I use text/javascript or application/javascript?
Use text/javascript. RFC 9239 designates it as the standard type; application/javascript is obsolete.
Why does my module script fail with a MIME type error?
The server is not sending a JavaScript media type. Modules require text/javascript or another registered JavaScript type, especially when nosniff is enabled.