what is AJAX exactly?

who is Ajax?

特洛伊(Troy)看过没？阿伽门侬(Agamemnon)手下除了阿基里斯（Achilles, 战神，敏捷型英雄）的排行老二的那个大个（ajax,使锤的，力量型的哈）。就是那后来被赫克托(Hektor,大王子)杀了（秒杀）的那个。

what is Ajax?

XMLHttpRequest + Javascript

what is XMLHttpRequest ?

look at this:

function new_XMLHttpRequest() {
var xmlreq = false;
if (window.XMLHttpRequest) {
xmlreq = new XMLHttpRequest();
}
else if (window.ActiveXObject) {
// Try ActiveX
try {
xmlreq = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e1) {
// first method failed
try {
xmlreq = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e2) {
// both methods failed
xmlreq = false;
}
}
}
return xmlreq;
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

what is Javascript

em… http://en.wikipedia.org/wiki/Javascript

我说: ajax 因为 XMLHttpRequest 而强大.

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }