AJAX Quick Glance: Part 3

new ActiveXObject(Microsoft.XMLHTTP)
This constructor is for Internet Explorer.

new XMLHttpRequest()
This constructor is for any other browser including Firefox.

http.onreadystatechange
An anonymous function is assigned to the event indicator.

http.readyState == 4
The 4 state means for the response is ready and sent by the server.

http.status == 200
This status means ok, otherwise some error code is returned, 404 for example.

http.open( "POST", "data.xml", true);
POST or GET
URL of the script to execute.
true for asynchronous (false for synchronous).

http.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
This is for POST only.

http.send(document.getElementById("TYPEDTEXT").value);
Send data to the server. Data comes from the "TYPEDTEXT" variable filled

throught the form by the user.