var http_request=false;
     function send_link()
     {  
        http_request=false;
       if(window.XMLHttpRequest)
       { 
			http_request=new XMLHttpRequest();
			if(http_request.overrideMimeType)
			{
				http_request.overideMimeType('text/xml');
			}
        }
       else if(window.ActiveXObject)
        {
             try{ hrrp_request=new ActiveXObject("Msxm12.XMLHTTP");}
             catch(e) { 
                          try{ http_request=new ActiveXObject("Microsoft.XMLHTTP");}
                          catch(e){}
                      }
       }
      if(!http_request) {
          //window.alert("不能创建XMLHTTPRequest 对象实例");
          return false;
        }
 
 
     }