function $(sid){return document.getElementById(sid)}
 
 /* 	
   XMLHttpRequest Object Pool 
 */ 
  var XMLHttp = { 
   _objPool: [], 
   

   _getInstance: function () { 
		for (var i = 0; i < this._objPool.length; i ++)  { 
			 if (this._objPool[i].readyState == 0 || this._objPool[i].readyState == 4)  { 
				 return this._objPool[i]; 
			 } 
		}    
	   // IE5中不支持push方法 
	   this._objPool[this._objPool.length] = this._createObj(); 
	   
	   return this._objPool[this._objPool.length - 1]; 
   }, 
   
   _createObj: function () { 
		if (window.XMLHttpRequest)  { 
			var objXMLHttp = new XMLHttpRequest(); 
   
		} 
		else { 
			var MSXML = ['MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP', 'Microsoft.XMLHTTP']; 
		   
			for(var n = 0; n < MSXML.length; n ++){ 
			   try  { 
				   var objXMLHttp = new ActiveXObject(MSXML[n]); 
				   break; 
			   } 
			   catch(e) { alert(e);} 
			} 
		}
   
	   // mozilla某些版本没有readyState属性 
	   if (objXMLHttp.readyState == null) { 
			objXMLHttp.readyState = 0; 
	   
			objXMLHttp.addEventListener("load", function (){ 
				objXMLHttp.readyState = 4; 
	   
				if (typeof objXMLHttp.onreadystatechange == "function")  { 
					objXMLHttp.onreadystatechange(); 
				} 
			 }, false); 
	   } 
   
	 return objXMLHttp; 
   }, 
   
   getXMLContent:function(){
		var objXMLHttp = this._getInstance(); 
		return objXMLHttp.responseXML;
   },

	getTextContent:function(){
		var objXMLHttp = this._getInstance(); 
		return objXMLHttp.responseText;
   },
   // 发送请求(方法[post,get], 地址, 数据, 回调函数) 
	sendRequest: function (method, url, data, callback) { 
		var objXMLHttp = this._getInstance(); 
		
	    with(objXMLHttp) { 
			try  { 
				// 加随机数防止缓存 
			   if (url.indexOf("?") > 0) { 
					url += "&randnum=" + Math.random(); 
			   } 
			   else { 
					url += "?randnum=" + Math.random(); 
			   } 
				
			   open(method, url, true); 
			  // 设定请求编码方式 
			   setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8'); 
			  if(method=="POST"){
			  	  send(data); 
			  }else{
				   send(null); 
			  }
			   onreadystatechange = function () { 
					if (objXMLHttp.readyState == 4 && objXMLHttp.status == 200)  { 
					//if (objXMLHttp.readyState == 4 && (objXMLHttp.status == 200 || objXMLHttp.status == 304))  { 
						callback();
					} 
				} 
		 }  catch(e) { 
			 alert(e); 
		} 
	} 
   } 
  }; 
  
  function getAuthorList(classid,suoying){
		var closeHtml='<div style="float:right;height:25px;width:50px;"><span style="float:left;"><img border=0 src=/pic/clearicon.gif /></span><span style="float:left;"><a href="javascript:void(0);" onclick="closeList()">关闭</a></span></div>';
		setInnerHTML('showlist','正在加载数据......');	
		XMLHttp.sendRequest('GET', '/showauthorlist.asp?cid='+classid+'&sy='+suoying, '',function(){
			setInnerHTML('showlist',closeHtml+XMLHttp.getTextContent()+"<br />"+closeHtml);	
		});
		
	}
	
	function setInnerHTML(sid,strHtml){
	
		if($(sid)){
			$(sid).innerHTML=strHtml;
		}else if(parent.$(sid)){
			parent.$(sid).innerHTML=strHtml;
		}
	}
	
	function showAuthorList(classid,suoying) {
		$("showlist").style.display="block";
		getAuthorList(classid,suoying);
	}
	function closeList(){
		setInnerHTML('showlist','');
		$("showlist").style.display="none";	
	}