// JavaScript Document  
    function popupDiv(div_id) {  
        var div_obj = $("#"+div_id); 
        var windowWidth = document.body.clientWidth;      
        var windowHeight = document.body.clientHeight; 
        var popupHeight = div_obj.height();      
        var popupWidth = div_obj.width();   
        //Ӳʾֲ  
        $("<div id='mask'></div>").addClass("mask")  
                                  .width(windowWidth + document.body.scrollWidth)  
                                  .height(windowHeight + document.body.scrollHeight)  
                                  .click(function() {hideDiv(div_id); })  
                                  .appendTo("body")  
                                  .fadeIn(100);  
        div_obj.css({"position": "absolute"})  
               .animate({left: windowWidth/2-popupWidth/2,   
                         top: windowHeight/50-popupHeight/20, opacity: "show" }, "slow");  
                       
    }  
     
    function hideDiv(div_id) {  
        $("#mask").remove();  
        $("#" + div_id).animate({left: 0, top: 0, opacity: "hide" }, "slow");  
    }