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 Firefox 132 and later [1] text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8Firefox 128 to 131 text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8Firefox 92 to 127 text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8Firefox 72 to 91 [2] text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8Firefox 66 to 71 [2] text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8Firefox 65 [2] text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8Firefox 64 and earlier [2] text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8Safari 13.1 to 18.1+ [4] text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8Chrome 131+ [4] text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7Safari, Chrome [4] text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8Safari 5 [3] text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8Edge 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.
[4] Rechecked and added values for Safari 13.1 to 18.1 and Chrome 131. Values may have changed before specified versions.
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=0.5Firefox 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=0.5Safari (since Mac OS Big Sur) image/webp,image/png,image/svg+xml,image/*;q=0.8,video/*;q=0.8,*/*;q=0.5Safari (before Mac OS Big Sur) image/png,image/svg+xml,image/*;q=0.8,video/*;q=0.8,*/*;q=0.5Chrome 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=0.5Firefox 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=0.5Safari, 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=0.1Safari, Chrome text/css,*/*;q=0.1Opera 11.10 text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1Konqueror 4.6 text/css,*/*;q=0.1
[1] See bug 170789.