File type / application
.js
Application-owned data: this family spans documents, archives, structured payloads, and software-specific files.
Best for: Workflows that need a format-aware viewer, editor, or parser rather than a generic media player.
Type family
application
Subtype
javascript
Default handling
Inline-capable
Handling verdict
Modern browsers can usually display this media type without downloading it first.
The registry explicitly declares UTF-8.
HTTP content encoding can usually reduce this format further.
This is readable code, but executing it can change the system or send data elsewhere.
HTTP response headers
Content-Type: application/javascript; charset=utf-8
Content-Disposition: inline; filename="example.js"
X-Content-Type-Options: nosniffThe MIME type describes the payload, Content-Disposition controls whether the browser previews or saves it, and nosniff prevents the browser from silently substituting a guessed type.
HTML file input
accept=".js,application/javascript"Use this value on <input type="file"> to steer the picker toward .js, its known aliases, and files reporting application/javascript. It improves selection, but it is not validation—check the bytes again after upload.
Registry ledger
declared valuesMIME type
application/javascript
Registry source
apache
Character set
UTF-8
Compressible
Yes
Known aliases
None listed
Same MIME type
No sibling record
How to work with .js
operational notesOpen it with the format-aware tool first
Start with A format-aware viewer, The software that created it, Developer tooling. Use the declared MIME type and an explicit Content-Disposition instead of relying on the filename alone. If the file came from someone else, keep the original untouched and work on a copy so a failed conversion cannot destroy the only source.
Safety note
This is readable code, but executing it can change the system or send data elsewhere.