List of default Accept 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 128 and later [1]	text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8
Firefox 92 to 127 [1]	text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Firefox 72 to 91 [2]	text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Firefox 66 to 71 [2]	text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Firefox 65 [2]	text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Firefox 64 and earlier [2]	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 [3]	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] The value can be set to an arbitrary string using the network.http.accept preference (about:config).

[2] The value can be set to an arbitrary string using the network.http.accept.default preference (about:config).

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

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 128 and later [1]	image/avif,image/webp,image/png,image/svg+xml,image/*;q=0.8,*/*;q=0.5
Firefox 92 to 127 [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] The value can be set to an arbitrary string using the image.http.accept parameter (source).

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	*/*

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.

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.

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.