js 遮罩层 loading 效果

function loadDiv(text) {
     var div = "<div id='_layer_'> <div id='_MaskLayer_' style='filter: alpha(opacity=30); -moz-opacity: 0.3; opacity: 0.3;background-color: #000; width: 100%; height: 100%; z-index: 1000; position: absolute;" +                 "left: 0; top: 0; overflow: hidden; display: none'></div><div id='_wait_' style='z-index: 1005; position: absolute; width:430px;height:218px; display: none'  ><center><h3>" +                 "" + text + "<img src='../images/loading.gif' /></h3><button onclick='LayerHide()'>关闭</button></center></div></div>"; 
   return div; 
}

function LayerShow(text) {
    var addDiv= loadDiv(text);  
  var element = $("#" + addDiv).appendTo(document.body);     $(window).resize(Position);  
   var deHeight = $(document).height();    
 var deWidth = $(document).width();    
 Position();     
$("#_MaskLayer_").show();   
  $("#_wait_").show();
 } 

 function Position() {  
 $("#_MaskLayer_").width($(document).width());   
  var deHeight = $(window).height();     
  var deWidth = $(window).width();     
  $("#_wait_").css({ left: (deWidth - $("#_wait_").width()) / 2 + "px", top: (deHeight - $("#_wait_").height()) / 2 + "px" }); 
}

 function LayerHide() { 
    $("#_MaskLayer_").hide(); 
    $("#_wait_").hide(); 
    del(); 
}

 function del() { 
 var delDiv = document.getElementById("_layer_");     delDiv.parentNode.removeChild(delDiv); 
 //删除 }