Load data dynamically on page scroll using jQuery, AJAX, and ASP.NET

Introduction

In Facebook you might see status updates of your friends dynamically loaded when you scroll the browser’s scroll bar. In this article I am going to explain how we can achieve this using jQuery and AJAX. 

Using the code

The solution includes two web forms (Default.aspx and AjaxProcess.aspx). The Default.aspx contains a Div with ID myDiv. Initially the Div contains some static data, then data is dynamically appended to it using jQuery and AJAX. 

<div id="myDiv">
	<p>Static data initially rendered.</p>
</div>

The second Web Form AjaxProcess.aspx contains a web method GetData() that is called using AJAX to retrieve data.

[WebMethod]
public static string GetData()
{
    string resp = string.Empty;
    resp += "<p>This content is dynamically appended to the existing content on scrolling.</p>";
    return resp;
}

Now we can add some jQuery script in Default.aspx that will be fired on page scroll and invokes the GetData()method.

$(document).ready(function () {

   $(window).scroll(function () {
       if ($(window).scrollTop() == $(document).height() - $(window).height()) {
           sendData();
       }
   });

   function sendData() {
       $.ajax(
        {
            type: "POST",
            url: "AjaxProcess.aspx/GetData",
            data: "{}",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            async: "true",
            cache: "false",

            success: function (msg) {
                $("#myDiv").append(msg.d);
            },

            Error: function (x, e) {
                alert("Some error");
            }
        });
   }
});

Here, to check whether the scroll has moved to the bottom, the following condition is used.

$(window).scroll(function () {
   if ($(window).scrollTop() == $(document).height() - $(window).height()) {
       sendData();
   }
});

This condition will identify whether the scroll has moved to the bottom or not. If it has moved to the bottom, dynamic data will get loaded from the server and get appended to myDiv.

success: function (msg) {
    $("#myDiv").append(msg.d);
},

History

Version 1.