webservice not returning values to on jquery ajax request - asp.net

Question

I would like consume cross-domain web-service from client with jquery.here is my code
function getId() {
var testid = ($('#<%=PreviousTest.ClientID %> OPTION:selected').val());
jQuery.support.cors = true;
jQuery.ajax({
type: "POST",
url: "../FalconWebService.asmx/minlatency",
data: "{'testId':" + testid + "}",
contentType: "application/json; charset=utf-8",
dataType:"json",
success: function (data) {
alert("catch");
var msg = jQuery.parseJSON(data.Table);
return msg;
},
Error: function () {
alert("error");
}
my webservice returns values in this format
{"Table":[{"minlatency":16.0,"Time":"/Date(1328248782660+0530)/"},{"minlatency":7.0,"Time":"/Date(1328248784677+0530)/"},{"minlatency":13.0,"Time":"/Date(1328248786690+0530)/"},{"minlatency":6.0,"Time":"/Date(1328248788690+0530)/"},{"minlatency":20.0,"Time":"/Date(1328248790707+0530)/"},{"minlatency":12.0,"Time":"/Date(1328248792723+0530)/"},{"minlatency":26.0,"Time":"/Date(1328248794723+0530)/"},{"minlatency":18.0,"Time":"/Date(1328248796723+0530)/"}]}

Answer 1

Calls in cross-domain work in a different way. They create dynamic javascripts that are inserted to the page using a callback function. This function is used to handle the response from the service. The Jquery calls add a "?callback=?" to the URL of the service, where "callback" is the name of the function that will be inserted.
To call cross-domain services with JQuery you have to do the following:
jQuery.ajax({
type: "POST",
url: "../FalconWebService.asmx/minlatency",
data: "{'testId':" + testid + "}",
contentType: "application/json; charset=utf-8",
dataType: "jsonp", //The data type that you must use is JSONP. Basically tells JQuery that the request is cross-domain
success: function (data) {
alert("catch");
var msg = jQuery.parseJSON(data.Table);
return msg;
},
Error: function () {
alert("error");
},
jsonpCallback: 'callback' //Dude to the fact that the JS is being generated dynamicaly, this tells JQuery to use the name "callback" for the function that will handle the result, as it adds "?callback=?" to the URL
});
You could also use "jsonp" instead of "jsonpCallback" if you want to "override the callback function name in a jsonp request" (from JQuery).
It worked for me (in WCF REST services which communicate with JSON messages, but it should work the same way in your case). This is all explained in the JQuery Ajax documentation.
Hope this helps.