Javascript知识拾遗:动态创建方法+多个异步监测

    这几天在做一个Web监测系统,需要对多个Server进行监测,采用的做法就是把需要监测的Server在页面上显示出来,然后通过Ajax对各个Server进行异步监测,开始的时候,针对每个Server,我都采用同一个JS方法循环和后台进行异步通信,结果程序一跑,发现根本不能做到同时异步监测多个Server,因此我想到了在Web页面Load的时候,根据后台返回的Server的个数,动态为每个Server创建不同的JS函数来处理异步通信请求。这样就可以做到同时异步监测多个Server。代码如下:

 

Html代码,被监测的Server列表:

<body onload="initializeMethod()">
<table width="500">
<tr>
<td width="100%">
      <table width="500" id="serverTab" border="1" cellpadding="0" cellspacing="0" align="left">
        <tr bgcolor="#0099CC">
        <td width="30%"><div align="center"> Host</div></td>
        <td width="15%"><div align="center"> Port</div></td>
        <td width="15%"><div align="center"> Interval(s)</div></td>
        <td width="35%"><div align="center"> Comment</div></td>
        </tr>
        <s:iterator value="serverListByType" id="serverList"  > 
        <tr>
        <td><div align="left"><s:property value="host" /> </div></td>
        <td><div align="left"><s:property value="port" /></div></td>
        <td><div align="left"><s:property value="interval" /></div></td>
        <td><div align="left"><s:property value="comment" /> </div></td>
        </tr>
         <br /> 
        		</s:iterator>
             </table>
             </td>
             </tr>


      </table>

</body>

 JS代码,动态生成异步监测函数:

    <script type="text/javascript">
    var functionArray = new Array();
    function initializeMethod(){

    	   var serverTab=document.getElementById("serverTab");
    	   for(var i = 1; i<=serverTab.rows.length-1; i++)
      	   {
    		   functionArray[i] = function(rowId){
    		      	var xmlHttp ; 
   		    	    if(window.XMLHttpRequest) {   
   		    	           
   		    	        xmlHttp = new XMLHttpRequest;      
   		    	           
   		    	    } else if (window.ActiveXObject) {   
   		    	           
   		    	        xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");   
   		    	    } else {   
   		    	           
   		    	        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");   
   		    	    }   
   		            var tab=document.getElementById("serverTab");
   		            var cbx = document.getElementsByName("server_id");
   					var interval = 0;
   					var first=true;
   					//tab.rows[rowId].bgColor='FFFFFF ';
   					//var minInterval = tab.rows[1].cells[3].children[0].value ;
   		            var ServerLists="";
 		                for(var j=0;j<tab.rows[rowId].cells.length;j++)
 		                {
 		                    for(var z=0;z<tab.rows[rowId].cells[j].children.length;z++)
 		                    {
 		                      var cb= tab.rows[rowId].cells[j].children[z];
 		                      ServerLists+=cb.innerText;
 		                      ServerLists+=",";
 		                    }

 		                }
 		                ServerLists+="\n";
     		    	    var url = "startMonitor"; 
     		    	    var param = "serverList="+ServerLists;
     		    	    xmlHttp.open("post",url,true);   
     		    	    xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
     		    	    xmlHttp.onreadyStatechange=function(){   

     		    	        if(xmlHttp.readyState==4) {   
     		    	            if( xmlHttp.status == 200 ){
         		    	                setInterval("functionArray["+rowId+"]("+rowId+")",interval); 
     		        	                 if(xmlHttp.responseText == 0)
     		           	                {
     		       	        	       tab.rows[rowId].bgColor='#FF0000 ';
     		           	                 }else
     		             	                {
     		           	        	     tab.rows[rowId].bgColor='#33FF33';
     		                                }
     		    	            } 
     		    	        } else {   

     		    	        }   
     		    	    }  
     		    	    xmlHttp.send(param); 


    		   };
      	   }

    	   refreshMonitorStatus();
    }
    	function  refreshMonitorStatus()
    	{
            var tab=document.getElementById("serverTab");
            var cbx = document.getElementsByName("server_id");
            for(var i=1;i<=tab.rows.length-1;i++)
            {
  	     tab.rows[i].bgColor='FFFFFF ';
          	    functionArray[i](i);
            }
       	}
    	    
        </script>

 

 

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