2. What is AJAX ? Ajax is a set of client side technologies that provides asynchronous communication between user interfaces and web server. So the advantages of using Ajax are asynchronous communication, minimal data transfer and server is not overloaded with unnecessary load.
10. Let’s see some coding : <html> <head> <script language = "javascript"> function GetXmlHttpObject() { if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari return new XMLHttpRequest(); } if (window.ActiveXObject) { // code for IE6, IE5 return new ActiveXObject ("Microsoft.XMLHTTP"); } return null; }
11. Let’s see some coding : var xmlhttp; function showUser(str) { xmlhttp= GetXmlHttpObject(); if (xmlhttp==null) { alert ("Browser does not support HTTP Request"); return; } var url="getselected.php"; url= url+"?id="+str; xmlhttp.onreadystatechange= stateChanged; xmlhttp.open ("GET“ ,url,true); xmlhttp.send(null); }
AJAX – has taken IT industry by storm. It might turn out to be one of the most demanded thing/in thing and hence, a brief presentation to understand AJAX. Be it anything that we are learning, asking 6 key questions is very important to get an overall idea of the same. The questions being – What, Why, Who, How, When and Where. So let’s being with what is AJAX? – not a technology, not a product … but an approach taken to develop Web Applications.
Inorder to understand what is this approach all about … let us first seek to know what the current approach is … At present, for every user interaction, the entire web page is rebuild. Even if a part of the entire page needs to be changed … we land up reloading the entire page. Which leads to … network traffic … slow speed … and most importantly … user experience goes down … user has to wait for loading of images … controls … which had already been loaded once!!! This is what AJAX asks us not to do.
