IE7-8 on windows 7 - strange request formats

does anyone know what is up with the request formats from IE running under windows 7?

i'm running a rails app that is checking on request.format. when going to something like http://localhost where there is no format specified in the url, i'm seeing:

Firefox request.forma开发者_运维百科t is 'html'

IE7 and IE8 running under windows 7 professional request.format is 'application/x-ms-application'

IE7 and IE8 running under windows 7 ultimate request.format is 'jpg'

i can't make heads or tails of it. has anyone else seen this?

Yep, I've come across this issue as well. For some reason the format header isn't being set by IE, in a lot of cases its simply '*/*' (xp, vista) etc.