js弹出遮罩层
js弹出层，并且遮罩下面内容， [ 注意，这里button为input其中的一种类型，不要换]
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>点击弹出居中的遮罩层代码</title>
<meta http-equiv="content-type" content="text/html;charset=gb2312">
<style type="text/css">
.hidden{display:none;}
#smallLay{498px; height:100px;padding:4px 10px 10px;background-color:#FFFFFF;border:1px solid #05549d;color:#333333;line-height:24px;text-align:left;-webkit-box-shadow:5px 2px 6px #000;-moz-box-shadow:3px 3px 6px #555;}
</style>
<script type="text/javascript">
function showid(idname){
var isIE = (document.all) ? true : false;
var isIE6 = isIE && ([/MSIE (d).0/i.exec(navigator.userAgent)][0][1] == 6);
var newbox=document.getElementById(idname);
newbox.style.zIndex="9999";
newbox.style.display="block"
newbox.style.position = !isIE6 ? "fixed" : "absolute";
newbox.style.top =newbox.style.left = "50%";
newbox.style.marginTop = - newbox.offsetHeight / 2 + "px";
newbox.style.marginLeft = - newbox.offsetWidth / 2 + "px";
var layer=document.createElement("div");
layer.></div>
</body>
</html>
代码参考自http://www.codefans.net/jscss/code/2312.shtml 经试验帮了我忙，抄下来，备忘