关闭窗口产生js的事件

/************ 关闭窗口，提交评价  **************/
    window.onbeforeunload = function(){
     var pageWidth = Math.max(window.top.document.body.scrollWidth, window.top.document.documentElement.scrollWidth);
     var pageHeight = Math.max(window.top.document.body.scrollHeight, window.top.document.documentElement.scrollHeight);
     var cltHeight = Math.max(window.top.document.body.clientHeight, window.top.document.documentElement.clientHeight);
  
     var width = 400 ;
     var height = 200 ;
  
     var layer = window.top.document.getElementById("zz_layer");
     if (layer != null) {
      layer.parentNode.removeChild(layer);
     }
      
     // 遮罩层
  var layer= window.top.document.createElement("div");
  layer.id = "zz_layer";
  layer.style.filter = "alpha(opacity=38)";//ie
  layer.style.opacity = "0.38";//ff
  layer.style.width = pageWidth + "px";
  layer.style.height = pageHeight + "px";
  layer.style.position= "absolute";
  layer.style.top = 0;
  layer.style.left = 0;
  layer.style.backgroundColor = "#000";
  layer.style.zIndex = "9998";
  window.top.document.body.appendChild(layer);

  // 评价窗口
  var newbox = document.getElementById("KF_PJ_DIV");
  newbox.style.zIndex = "9999";
  newbox.style.display = "block";
  newbox.style.width = width + "px";
  newbox.style.height = height + "px";
  newbox.style.border = "#565656 4px solid";
  newbox.style.background = "#FFFFFF";
  newbox.style.position = "absolute";
  newbox.style.left = pageWidth/2 + "px";
  newbox.style.top = (cltHeight/2) + "px";

  if(height/2 > (cltHeight/2)){
   newbox.style.marginTop = ( - (cltHeight/2)) + "px";
  }else{
   newbox.style.marginTop = ( - height/2) + "px";
  }
  if(width/2 > (pageWidth/2)){
   newbox.style.marginLeft = ( - (pageWidth/2)) + "px";
  }else{
   newbox.style.marginLeft = ( - width/2) + "px";
  }
    
     return "您尚未对客服服务作出评价，请点击‘取消’评分！";
   };

   function mydiv_resize(){
    var pageWidth = Math.max(window.top.document.body.scrollWidth, window.top.document.documentElement.scrollWidth);
     var pageHeight = Math.max(window.top.document.body.scrollHeight, window.top.document.documentElement.scrollHeight);
     var cltHeight = Math.max(window.top.document.body.clientHeight, window.top.document.documentElement.clientHeight);
     var cltWidth = Math.max(window.top.document.body.clientWidth, window.top.document.documentElement.clientWidth);
  
     var width = 400 ;
     var height = 200 ;
     
    var layer = window.top.document.getElementById("zz_layer");
     if (layer != null) {
      // 遮罩层
   layer.style.width = pageWidth + "px";
   layer.style.height = pageHeight + "px";
     }
      
  // 评价窗口
  var newbox = document.getElementById("KF_PJ_DIV");
  newbox.style.left = cltWidth/2 + "px";
  newbox.style.top = (cltHeight/2) + "px";

  if(height/2 > (cltHeight/2)){
   newbox.style.marginTop = ( - (cltHeight/2)) + "px";
  }else{
   newbox.style.marginTop = ( - height/2) + "px";
  }
  if(width/2 > (pageWidth/2)){
   newbox.style.marginLeft = ( - (pageWidth/2)) + "px";
  }else{
   newbox.style.marginLeft = ( - width/2) + "px";
  }
   }
   
 window.onresize = mydiv_resize;