/*
	示例
	function callBack()
	{
		locatiion.reload(true);
	}
	
	new Ajax("/index.aspx", "a=1&b=2", callBack, "post", "delete");
	0:	请求地址
	1:	查询字符串（不包含"?"和操作名）,字符串类型参数必须经过encodeURIComponent处理，不可以使用escape
	2:	回调函数
	3:  请求方式，"post" 或者 "get"
	4： 操作名
	create_date:2008.10.9
	author:stupidliao
*/


function Ajax(url, params, callBack, method, optName)
{
    var xhr = null;
    if(window.XMLHttpRequest)
    {
        xhr = new XMLHttpRequest();
    }
    else
    {
    	xhr = new ActiveXObject('Msxml2.XMLHTTP') || new ActiveXObject('Microsoft.XMLHTTP');
    }  
	this.stateChange = function() 
	{
	  	if (xhr.readyState == 4) 
		{
	    	if(callBack && typeof callBack == "function")
	    	{
	        	callBack(xhr.responseText);
	    	}	
  		}
	};

	if (method.toUpperCase() == "GET") 
	{
	    if (optName != "")
	        xhr.open(method, url + "?" + params + "&ajaxMethod=" + optName, true);
	    else
	        xhr.open(method, url + "?" + params, true);
	}
	else
	{
		xhr.open(method, url, true);
		
	}
	xhr.onreadystatechange = this.stateChange;
	xhr.setRequestHeader("QIDIANSNSAJAX-Ver","ver1.0");
	if(method.toUpperCase() == "GET")
	{
		xhr.send(null);
	}
	else
	{
	    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	    if (optName != "")
	        xhr.send(params + "&ajaxMethod=" + optName);
	    else
	        xhr.send(params);
	}
}