Default values
These are the values sent when the context doesn't give better information. Note that all browsers add the */* MIME Type to cover all cases. This is typically used for requests initiated via the address bar of a browser, or via an HTML <a> element.
| User Agent | Value | Comment |
|---|---|---|
| Firefox | text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 |
This value can be modified using the network.http.accept.default parameter. |
| Safari, Chrome |
|
source |
| Safari 5 |
|
This is an improvement over earlier Accept headers as it no longer ranks image/png above text/html |
| Internet Explorer 8 | image/jpeg, application/x-ms-application, image/gif, application/xaml+xml, image/pjpeg, application/x-ms-xbap, application/x-shockwave-flash, application/msword, */* |
See IE and the Accept Header (IEInternals' MSDN blog). |
| Edge | */* |
|
| Opera | text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1 |
Values for an image
When requesting an image, like through an HTML <img> element, user-agent often sets a specific list of media types to be welcomed.
| User Agent | Value | Comment |
|---|---|---|
| Firefox | */* (since Firefox 47)image/png,image/*;q=0.8,*/*;q=0.5 (before) |
This value can be modified using the image.http.accept parameter. |
| Safari | */* |
|
| Chrome | image/webp,image/*,*/*;q=0.8 |
Was */* before the support for webp |
| Internet Explorer 8 or earlier | */* |
See IE and the Accept Header (IEInternals' MSDN blog) |
| Internet Explorer 9 | image/png,image/svg+xml,image/*;q=0.8, */*;q=0.5 |
See Fiddler is better with Internet Explorer 9 (IEInternals' MSDN blog) |
Values for a video
When a video is requested, via the <video> HTML element, most browsers use specific values.
| User Agent | Value | Comment |
|---|---|---|
| Firefox earlier than 3.6 | no support for <video> |
|
| Firefox 3.6 and later | audio/webm, audio/ogg, audio/wav, audio/*;q=0.9, application/ogg;q=0.7, video/*;q=0.6; */*;q=0.5 |
See bug 489071 |
| Chrome | */* |
|
| Internet Explorer 8 or earlier | no support for <video> |
Values for audio resources
When an audio file is requested, like via the <audio> HTML element, most browsers use specific values.
| User Agent | Value | Comment |
|---|---|---|
| Firefox 3.6 and later | audio/webm,audio/ogg,audio/wav,audio/*;q=0.9,application/ogg;q=0.7,video/*;q=0.6,*/*;q=0.5 |
See bug 489071 |
| Safari, Chrome | ? | |
| Internet Explorer 8 or earlier | no support for <audio> |
|
| Internet Explorer 9 | ? |
Values for scripts
When a script is requested, like via the <script> HTML element, some browsers use specific values.
| User Agent | Value | Comment |
|---|---|---|
| Firefox | */* |
See bug 170789 |
| Safari, Chrome | */* |
|
| Internet Explorer 8 or earlier | */* |
See IE and the Accept Header (IEInternals' MSDN blog) |
| Internet Explorer 9 | application/javascript, */*;q=0.8 |
See Fiddler is better with Internet Explorer 9 (IEInternals' MSDN blog) |
Values for a CSS stylesheet
When a CSS stylesheet is requested, via the <link rel="stylesheet"> HTML element, most browsers use specific values.
| User Agent | Value | Comment |
|---|---|---|
| Firefox 4 | text/css,*/*;q=0.1 |
See bug 170789 |
| Safari 5 | text/css,*/*;q=0.1 |
|
| Internet Explorer 8 or earlier | */* |
See IE and the Accept Header (IEInternals' MSDN blog) |
| Internet Explorer 9 | text/css |
See Fiddler is better with Internet Explorer 9 (IEInternals' MSDN blog) |
| Chrome 12 | text/css,*/*;q=0.1 |
|
| Opera 11.10 | text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1 |
|
| Konqueror 4.6 | text/css,*/*;q=0.1 |