一个封装的Ajax类

// Ajax 封装 2007-3-13
function createXMLHttpRequest() {
try {
if (window.XMLHTTPRequest) {
return new XMLHttpRequest();
}
else if (window.ActiveXObject) {
return new ActiveXObject("Microsoft.XMLHTTP");
}
}
catch (e) {alert("XMLHttpRequest对象无法创建！请检查IE安全设置！");}
}
function messageDiv(t)
{
var v = document.createElement("<div>");
v.innerHTML = "<table style=/"width:300px;/" id=message>" +
"<tr style=/"font-size:12px;background-color:#EEEEff;color:#227933;height:20px/">" +
"<td style=/"padding:2px;border-top:1px solid #E1E1E1;border-left:1px solid #E1E1E1;border-bottom:1px solid #818181;border-right:1px solid #A1A1A1/">" +
"<nobr><img src=refresh.gif align=absmiddle> " + t + ",<span id=Span1>连接未初始化...</span></nobr></td></tr></table>";
var l = document.getElementsByName("message").length;
v.style.cssText = "position:absolute;bottom:" + (l*24) + "px;left:0px;display:none";
document.body.appendChild(v);
this.clear = function () {
document.body.removeChild(v);
var msg = document.getElementsByName("message");
for (var i=0;i<msg.length;i++){
msg[i].parentNode.style.cssText = "position:absolute;bottom:" + (i*24) + "px;left:0px";
}
}
this.showmsg = function (s) {
v.style.display = "";
v.all.Span1.innerHTML = s;
}
}
function Ajax() {
var x = new createXMLHttpRequest();
this.Request = function (url,cmd,async,method,postString,title) {
if (method!="post") method = "post"; else method = "get";
if (async!=true) async = true; else async = false;
if (typeof(postString)!="string") postString="";
if (typeof(title)!="string") + title;
var msgbox = new messageDiv(title);
x.onreadystatechange = function ()
{
if (async) switch (x.readystate) {
case 1:
msgbox.showmsg("正在初始化连接...");
return;
case 2:
msgbox.showmsg("正在发送数据...");
return;
case 3:
msgbox.showmsg("正在接收数据...");
return;
case 4:
msgbox.showmsg("数据接收完成...");
if (x.status == 200) {
cmd(x.responseText);
msgbox.clear();
}
else {
msgbox.showmsg("请求失败," + x.statustext + "(" + x.status + ")");
setTimeout(msgbox.clear,3000);
}
return;
}
}
x.open (method,url,async);
if (method=="post") {msgbox.showmsg("正在接收数据...");x.send(postString);} else x.send();
if (!async) {
msgbox.showmsg("数据接收完成...");
cmd(x.responseText);
msgbox.clear();
}
}
}