function XMLHttpClient(instanceName)
{
	this.instanceName=instanceName;
	
	this.xmlhttp = false;
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
	   this.xmlhttp = new XMLHttpRequest();
	   if (this.xmlhttp.overrideMimeType) {
		   this.xmlhttp.overrideMimeType('text/xml');
	   }
	} else if (window.ActiveXObject) { // IE
		try {
			this.xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				this.xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {}
		}
	}
	if (!this.xmlhttp) {
		alert('无法创建组件：XMLHTTP，可能由于浏览器版本太低或浏览器部分组件已损坏。');
	}
}

XMLHttpClient.prototype.open=function(method,url,Async)
{
	this.xmlhttp.open(method,url,Async);
	if (method == "POST"||method == "post") {
		this.xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
	}
}

XMLHttpClient.prototype.attachOnChange=function(instanceName)
{
	this.xmlhttp.onreadystatechange=function()
	{
		if(window[instanceName].xmlhttp.readyState==4)
		{
			window[instanceName].fireOnStatus(window[instanceName].xmlhttp.status);
		}
	}
}

XMLHttpClient.prototype.getState=function()
{
	return this.xmlhttp.readyState;
}

XMLHttpClient.prototype.setRequestHeader=function(header,value)
{
	this.xmlhttp.setRequestHeader(header,value);
}

XMLHttpClient.prototype.send=function(post_data)
{
	this.xmlhttp.send(post_data);
	this.attachOnChange(this.instanceName);
}

XMLHttpClient.prototype.attachOnStatus=function(Status,func)
{
	this["onStatus_"+Status.toString()]=func;
}

XMLHttpClient.prototype.fireOnStatus=function(status)
{
	if(this["onStatus_"+status])
		this["onStatus_"+status](this.xmlhttp);
	else
		this["onStatus_default"](this.xmlhttp);
}


XMLHttpClient.prototype.onStatus_default=function(xmlhttp)
{
	alert("通讯异常，错误号："+xmlhttp.status.toString()+"！");
}