This article documents the default values for the HTTP Accept header for specific inputs and browser versions.
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 |
| This value can be modified using the network.http.accept.default parameter. source
|
| 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 | text/html, application/xhtml+xml, image/jxr, */* | |
| 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 |
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 |
| This value can be modified using the image.http.accept parameter. source
|
| Safari | */* | |
| Chrome | image/webp,image/apng,image/*,*/*;q=0.8 | source |
| 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) |
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 | video/webm,video/ogg,video/*;q=0.9,application/ogg;q=0.7,audio/*;q=0.6,*/*;q=0.5 | See bug 489071 source |
| Chrome | */* | source |
| Internet Explorer 8 or earlier | no support for <video> |
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 source |
| Safari, Chrome | */* | source |
| Internet Explorer 8 or earlier | no support for <audio> | |
| Internet Explorer 9 | ? |
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 | */* | source |
| 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) |
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 source |
| 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) |
| Safari, Chrome | text/css,*/*;q=0.1 | source |
| 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 |
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https://developer.mozilla.org/en-US/docs/Web/HTTP/Content_negotiation/List_of_default_Accept_values