List of default Accept values
=============================

This article documents the default values for the HTTP `Accept` header for specific inputs and browser versions.

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 |
| --- | --- |
| Firefox 92 and later [1] | `text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8` |
| Firefox 72 to 91 [1] | `text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8` |
| Firefox 66 to 71 [1] | `text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8` |
| Firefox 65 [1] | `text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8` |
| Firefox 64 and earlier [1] | `text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8` |
| Safari, Chrome | `text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8` |
| Safari 5 [2] | `text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8` |
| 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` |

[1] This value can be modified using the `network.http.accept.default` parameter.

[2] This is an improvement over earlier `Accept` headers as it no longer ranks `image/png` above `text/html`.

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 |
| --- | --- |
| Firefox 92 and later [1] | `image/avif,image/webp,*/*` |
| Firefox 65 to 91 [1] | `image/webp,*/*` |
| Firefox 47 to 63 [1] | `*/*` |
| Firefox prior to 47 [1] | `image/png,image/*;q=0.8,*/*;q=0.5` |
| Safari (since Mac OS Big Sur) | `image/webp,image/png,image/svg+xml,image/*;q=0.8,video/*;q=0.8,*/*;q=0.5` |
| Safari (before Mac OS Big Sur) | `image/png,image/svg+xml,image/*;q=0.8,video/*;q=0.8,*/*;q=0.5` |
| Chrome and Edge 121 and later | `image/avif,image/webp,image/apng,image/*,*/*;q=0.8` |

[1] This value can be modified using the `image.http.accept` parameter (*source*).

Values for a video
------------------

When a video is requested, via the `<video>` HTML element, most browsers use specific values.

| User Agent | Value |
| --- | --- |
| 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` |
| Firefox earlier than 3.6 | *no support for `<video>`* |
| Chrome | `*/*` |

Values for audio resources
--------------------------

When an audio file is requested, like via the `<audio>` HTML element, most browsers use specific values.

| User Agent | Value |
| --- | --- |
| Firefox 3.6 and later [1] | `audio/webm,audio/ogg,audio/wav,audio/*;q=0.9,application/ogg;q=0.7,video/*;q=0.6,*/*;q=0.5` |
| Safari, Chrome | `*/*` |

[1] See bug 489071.

Values for scripts
------------------

When a script is requested, like via the `<script>` HTML element, some browsers use specific values.

| User Agent | Value |
| --- | --- |
| Firefox [1] | `*/*` |
| Safari, Chrome | `*/*` |

[1] See bug 170789.

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 |
| --- | --- |
| Firefox 4 [1] | `text/css,*/*;q=0.1` |
| Safari, Chrome | `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` |

[1] See bug 170789.