[jQuery] why my ajax call is not working in IE?

[jQuery] why my ajax call is not working in IE?


Following code works in firefox, but doesn't work in IE. why?
sendRequest:function(mode, request, argument)
    {
        if(mode=="prototype")
        return $.ajax({
    url: "xml/"+request+".xml",
    error: function(){
        alert('Error loading xml');
            },
    async: false,});
        else
        {
         var queryStr='';
         if(request=="summary")
             queryStr='opcode=get_data&type=8';
         else if(request=="connectivity")
             queryStr='opcode=get_data&type=4';
         else if(request=="ping")
         queryStr='opcode=execute&cmd=ping&argument=' + argument;
         return $.ajax({
             type: "get",
    url: rap_util.urlroot,
    data: queryStr,
    error: function(){
        alert('Error loading '+request);
            },
    async: false,
    dataType: 'xml'});
        }
    },