IE FF OPERA都可用的弹出层实现代码

// JavaScript Document 
var dv; 
var dvMsg; 
function customalert() 
{ dvMsg = document.createElement("div"); 
dvMsg.style.position = "absolute"; 
dvMsg.setAttribute('id', 'msg'); 
dvMsg.style.width = "600px"; 
dvMsg.style.padding = "10 0 2 0"; 
dvMsg.style.height = "313px"; 
dvMsg.style.background = "#EF621D"; 
dvMsg.style.border = "1px solid #6699dd"; 
dvMsg.style.zIndex = "1112"; 
document.body.appendChild(dvMsg); 
document.getElementById("msg").style.top = document.documentElement.scrollTop + (document.documentElement.clientHeight - document.getElementById("msg").offsetHeight)/2 + "px"; 
document.getElementById("msg").style.left = document.documentElement.scrollLeft + (document.documentElement.clientWidth - document.getElementById("msg").offsetWidth)/2 + "px"; 
var imgs = document.createElement("div"); 
imgs.setAttribute("id", "pic"); 
imgs.title = "close"; 
imgs.style.float = "left"; 
imgs.style.height = "20px"; 
imgs.innerHTML = "<a href=\"https://3water.com\" target=\"_blank\"><img src=\"../javascript/close.gif\"/></a>"; 
imgs.style.color = "#FFF"; 
imgs.style.textAlign = "right"; 
imgs.style.cursor = "pointer"; 
imgs.style.zIndex = "1114"; 
imgs.onclick = function() 
{ 
document.body.removeChild(dvMsg); 
document.body.removeChild(dv); 
} 
document.getElementById("msg").appendChild(imgs); 
var divstr = document.createElement("div"); 
divstr.setAttribute("id", "info"); 
divstr.style.left = "0"; 
divstr.style.position = "absolute"; 
divstr.style.marginTop = "10px"; 
divstr.style.zIndex = "1115"; 
divstr.innerHTML = "<embed src=\"gallery/header2.swf\" pluginspage=\"http://www.macromedia.com/shockwave/download /\" width=\"600\" height=\"313\"></embed>"; 
document.getElementById("msg").appendChild(divstr); 
} 
function scrolldivs() 
{ 
document.getElementById("msg").style.top=document.documentElement.scrollTop+(document.documentElement.clientHeight-document.getElementById("msg").offsetHeight)/2+"px"; 
document.getElementById("msg").style.left=document.documentElement.scrollLeft+(document.documentElement.clientWidth-document.getElementById("msg").offsetWidth)/2+"px"; 
} 
window.attachEvent("onresize",scrolldivs); 
window.onscroll=scrolldivs; 
window.onload=scrolldivs;