Ajax get和Post的纯js实现代码

<span style="font-size:18px;">//AJAX类
function AjaxClass()
{
var XmlHttp = false;
try
{
XmlHttp = new XMLHttpRequest();        //FireFox专有
}
catch(e)
{
try
{
XmlHttp = new ActiveXObject("MSXML2.XMLHTTP");
}
catch(e2)
{
try
{
XmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
catch(e3)
{
alert("你的浏览器不支持XMLHTTP对象，请升级到IE6以上版本！");
XmlHttp = false;
}
}
}

var me = this;
this.Method = "POST";
this.Url = "";
this.Async = true;
this.Arg = "";
this.CallBack = function(){};
this.Loading = function(){};

this.Send = function()
{
if (this.Url=="")
{
return false;
}
if (!XmlHttp)
{
return IframePost();
}

XmlHttp.open (this.Method, this.Url, this.Async);
if (this.Method=="POST")
{
XmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
}
XmlHttp.onreadystatechange = function()
{
if (XmlHttp.readyState==4)
{
var Result = false;
if (XmlHttp.status==200)
{
Result = XmlHttp.responseText;
}
XmlHttp = null;

me.CallBack(Result);
}
else
{
me.Loading();
}
}
if (this.Method=="POST")
{
XmlHttp.send(this.Arg);
}
else
{
XmlHttp.send(null);
}
}

//Iframe方式提交
function IframePost()
{
var Num = 0;
var obj = document.createElement("iframe");
obj.attachEvent("onload",function(){ me.CallBack(obj.contentWindow.document.body.innerHTML); obj.removeNode() });
obj.attachEvent("onreadystatechange",function(){ if (Num>=5) {alert(false);obj.removeNode()} });
obj.src = me.Url;
obj.style.display = 'none';
document.body.appendChild(obj);
}
}

/*----------------------------调用方法------------------------------
var Ajax = new AjaxClass();			// 创建AJAX对象
Ajax.Method = "POST"; 				// 设置请求方式为POST
Ajax.Url = "default.asp"			// URL为default.asp
Ajax.Async = true;					// 是否异步
Ajax.Arg = "a=1&b=2";				// POST的参数
Ajax.Loading = function(){			//等待函数
document.write("loading...");
}
Ajax.CallBack = function(str)       // 回调函数
{
document.write(str);
}
Ajax.Send();            			// 发送请求
-----------------------------------------------------------
var Ajax = new AjaxClass();			// 创建AJAX对象
Ajax.Method = "GET"; 				// 设置请求方式为POST
Ajax.Url = "default.asp?a=1&b=2"	// URL为default.asp
Ajax.Async = true;					// 是否异步
Ajax.Loading = function(){			//等待函数
document.write("loading...");
}
Ajax.CallBack = function(str)       // 回调函数
{
document.write(str);
}
Ajax.Send();           				// 发送请求
--------------------------------------------------------------------*/ </span>