Question

I have created a webservice and want to call it from javascript , for this I have registered ServiceReference in my page’s script manager, and called webservice using namespace.

My problem is that I want to wait until response from webservice received.

For this I was trying to using setInterval but that does not work.

Any other way to achieve this?

More Details are below:
In Javascript If you write a function to call WebService you have to pass it a method signature that will be called after webservice sends response.

e.g.

var IsResponseReceived;
function GetSomethingFromWebService()
{
  IsResponseReceived = 'No';
  Namespace.WebServiceClass.GetMeSomething(parameter1,SuccessResponseReceiver);
  alert(webServiceResponse);
}

function SuccessResponseReceiver(parameter1,parameter2)
{
  IsResponseReceived = 'Yes';
}

In the above code my alert gives me ‘No’ everytime. I want to write someline inbetween alert and webservice call that should let me wait until I get response.

Am I Clear now?

Answer 1

If you consider using pure JavaScript (pretty unusual these days), consider this code

var strURL = "localhost/services/foobar.svc";
var xmlHttpReq = false;
var self = this;
// Mozilla/Safari
if (window.XMLHttpRequest) {
    self.xmlHttpReq = new XMLHttpRequest();
}
// IE
else if (window.ActiveXObject) {
    self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
}
self.xmlHttpReq.open('GET', strURL, true);
self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
self.xmlHttpReq.onreadystatechange = function() {
    if (self.xmlHttpReq.readyState == 4) {
        // do whatever you want to do when your service responded
        // you may get the response content using self.xmlHttpReq.responseText
    }
}
self.xmlHttpReq.send();

If you consider using jQuery (this one of the popular JavaScript framework around), its easy:

$.ajax({
  url: "localhost/services/foobar.svc",
  success: function(data){
    // this is fired on successful response
    // you will have response content in data parameter
  }
});