HTTP Accept Header meaning

Question

When a browser\'s Accept request header says something like the following:

Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,ima         


        

Answer 1

No, if the quality parameter is missing q=1.0 is assumed:

Each media-range MAY be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative quality factor […] using the qvalue scale from 0 to 1 (section 3.9). The default value is q=1.

So the given value is to be interpreted as: “application/xml, application/xhtml+xml, and image/png are the preferred media types, but if they don’t exist, then send the text/html entity (text/html;q=0.9), and if that doesn’t exist, then send the text/plain entity (text/plain;q=0.8), and if that doesn’t exist, send an entity with any other media type (*/*;q=0.5).”