when call the webservice using jquery every time it shown er

when call the webservice using jquery every time it shown error with googlecrome
what is the problem.


 var param = 'firstname=' + firstname+ '&dob=' + dob + '&mobileno=' + mobileno 
$.ajax({                 type: "POST",                 url: "MyWebService.asmx/SayHello",                 data:param , 

                //contentType: "application/x-www-form-urlencoded; charset=UTF-8", // if you are using form encoding, this is default so you don't need to supply it                 dataType: "text", // the data type we want back, so text.  The data will come wrapped in xml                 success: function (data) {                     $("#searchresultsA").html(data); // show the string that was returned, this will be the data inside the xml wrapper                 }

                  error:function(a,b,c)
{
         
}             });