JavaScript实现网页右下角弹出提示框

<!DOCTYPE html>
<html>
<head>
<meta charset="gb2312">
<title>网页右下角的信息框</title>
</head>
<style type="text/css">
#winpop {
 width:200px;
 height:0px;
 position:absolute;
 right:0;
 bottom:0;
 border:1px solid #666;
 margin:0;
 padding:1px;
 overflow:hidden;
 display:none;
}
#winpop .title{
 width:100%;
 height:22px;
 line-height:20px;
 background:#FFCC00;
 font-weight:bold;
 text-align:center;
 font-size:12px;
}
#winpop .con{
 width:100%;
 height:90px;
 line-height:80px;
 font-weight:bold;
 font-size:12px;
 color:#FF0000;
 text-decoration:underline;
 text-align:center
}
#silu{
 font-size:12px;
 color:#666;
 position:absolute;
 right:0;
 text-decoration:underline;
 line-height:22px;
}
.close{
 position:absolute;
 right:4px;
 top:-1px;
 color:#FFF;
 cursor:pointer
}
</style>
<script type="text/javascript">
function tips_pop(){
 var MsgPop=document.getElementById("winpop");
 var popH=parseInt(MsgPop.style.height);//将对象的高度转化为数字
 if(popH==0){
 MsgPop.style.display="block";//显示隐藏的窗口
 show=setInterval("changeH('up')",2);
 }
 else{ 
 hide=setInterval("changeH('down')",2);
 }
}
function changeH(str){
 var MsgPop=document.getElementById("winpop");
 var popH=parseInt(MsgPop.style.height);
 if(str=="up"){
 if(popH<=100){
 MsgPop.style.height=(popH+4).toString()+"px";
 }
 else{ 
 clearInterval(show);
 }
 }
 if(str=="down"){ 
 if(popH>=4){ 
 MsgPop.style.height=(popH-4).toString()+"px";
 }
 else{ 
 clearInterval(hide); 
 MsgPop.style.display="none"; //隐藏DIV
 }
 }
}
window.onload=function(){
 var oclose=document.getElementById("close");
 var bt=document.getElementById("bt");
 document.getElementById('winpop').style.height='0px';
 setTimeout("tips_pop()",3000);
 oclose.onclick=function(){tips_pop()}
 bt.onclick=function(){tips_pop()}
}
</script>
<body>
<div id="silu">
 <button id="bt">3秒后会在右下角自动弹出窗口，如果没有弹出请点击这个按钮</button>
</div>
<div id="winpop">
 <div class="title">您有新的短消息！<span class="close" id="close">X</span></div>
 <div class="con">1条未读信息(</div>
</div>
</body>
</html>

#winpop {
 width:200px;
 height:0px;
 position:absolute;
 right:0;
 bottom:0;
 border:1px solid #666;
 margin:0;
 padding:1px;
 overflow:hidden;
 display:none;
}