Call Server side function from Javascript in ASP.NET

The "standard" way to do this in ASP.NET now, is to use AJAX. It's possible to use MS AJAX to accomplish this, but I prefer to use jQuery's Ajax calls.

What you do is create a ScriptService in your ASP.NET project, add the serverside code as a WebMethod, and then call it from your javascript. If you don't want to add a ScriptService, you can add the WebMethod to a Page. Here's a typical ajax call from jQuery:

$.ajax({
      type: "POST",
      url: "MyScriptService.asmx/GetDate",
      data: "{}",
      contentType: "application/json; charset=utf-8",
      dataType: "json",
      success: function(msg) {
        alert(msg.d);
      }
    });