Ajax: A Web Development technology (asynchronous Javascript + XML)

2. Create a new XMLHttpRequest object (the core of an Ajax application):
   

   <script language= "javascript" type= "Text/javascript" >    var xmlHttp = new XMLHttpRequest ();</script>

4. Capturing and setting field values with JavaScript code

   Gets the form field with the ID value first_name var name = document.getElementById (' first_name '). value;//Modify the value of the form field with the ID value test document.getelemen Tbyid (' Test '). Value = Response[0];

   　　

6. Create a XMLHttpRequest object on a Microsoft browser

   var xmlHttp = false;try {  xmlHttp = new ActiveXObject ("Msxml2.xmlhttp");} catch (e) {  try {    xmlHttp = new Acti Vexobject ("Microsoft.XMLHTTP");  } catch (E2) {    xmlHttp = false;  }}

   　　

8. create XMLHttpRequest objects in a way that supports multiple browsers

   /* Create a new XMLHttpRequest object to talk to T He Web server */var xmlHttp = false;/* @cc_on @*//* @if (@_jscript_version >= 5) try {xmlHttp = new ActiveXObject ("Msxml 2.XMLHTTP ");}  catch (e) {try {xmlHttp = new ActiveXObject ("Microsoft.XMLHTTP");  } catch (e2) {xmlHttp = false; }} @end @*/if (!xmlhttp && typeof XMLHttpRequest! = ' undefined ') {xmlHttp = new XMLHttpRequest ();} 

10. Getting started: Sending Ajax requests

    function CallServer () {  //Get the city and state from the Web Form  var city   = document.getElementById ("City") . value;  var state = document.getElementById ("state"). Value;  Build the URL to connect to  var url = '/scripts/getzipcode.php?city= ' + Escape (city) + ' &state= ' + Escape (state );  Open a connection to the server  xmlhttp.open ("GET", url, true);  Setup a function for the server to run when it's done  xmlhttp.onreadystatechange = updatepage;  Send the request  xmlhttp.send (null);}

    　　

Ajax: A Web Development technology (asynchronous Javascript + XML)