Question

This piece of javascript always returns null in firefox & chrome, but works fine in internet explorer:

  $.ajax({
    url: "http://mymachine/mywebservice.asmx/myfunction",
    data: "{ 'q': 'hotels', 'limit': '10' }",
    dataType: "json",
    type: "POST",
    contentType: "application/json; charset=utf-8",
    dataFilter: function (data) { return data; },
    success: function (data) {
        alert(data == null);
    }
  });

Looking in fiddler, the IE request looks like this:

POST http://remotemachine/webservice.asmx/functionname HTTP/1.1
Content-Type: application/json; charset=utf-8
Accept-Language: en-gb
Referer: http://localmachine/
Accept: application/json, text/javascript, */*
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; OfficeLiveConnector.1.3; OfficeLivePatch.0.0; .NET4.0C; .NET4.0E)
Host: test.maznet.biz
Content-Length: 32
Connection: Keep-Alive
Pragma: no-cache

{ 'q': 'hotels', 'limit': '10' }

The firefox request, running exactly the same javascript, looks like this:

OPTIONS http://remotemachine/webservice.asmx/functionname HTTP/1.1
Host: remotehost
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-GB; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 GTB7.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-gb,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
Origin: http://mymachine
Access-Control-Request-Method: POST

Edit: ive amended the exact function names and domains for anonimity, so forgive any typos

Answer 1

Oh my, five hours of working on this, ive just found the answer. Firefox/Chrome will not allow cross domain JSON requests, hence it working in good old slack security IE8, and not in the more ‘secure’ browsers. Doh!