纯CSS实现圆角、可拖动的一个DIV模块层

<style>
body{
margin:0px;
padding:0px;
font-size:14px;
}
#t {
position:absolute;
float:left;
left:0px;
top:0px;
}
#a {
float:left;
}
.al {
opacity: 0.80;
filter : progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=80,finishOpacity=100);
}
.al2{
opacity: 0.00;
filter : progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0,finishOpacity=100);
}
U {
DISPLAY: block;
OVERFLOW: hidden;
HEIGHT: 1px
}
U.f1 {
background-color:#5cc;
BACKGROUND: #5cc;
MARGIN: 0px 3px
}
U.f2 {
background-color:#5cc;
BORDER-RIGHT: #5cc 2px solid;
MARGIN: 0px 1px;
BORDER-LEFT: #5cc 2px solid
}
U.f3 {
background-color:#5cc;
BORDER-RIGHT: #5cc 1px solid;
MARGIN: 0px 1px;
BORDER-LEFT: #5cc 1px solid
}
.d_top{
clear:both;
overflow:hidden;
background-color:#5cc;
height:29px;
vertical-align:bottom;
}
.d_top a{
float:right;
margin-top:5px;
margin-right:13px;
padding-top:3px;
18px;
color:red;
background-color:#789;
text-decoration:none;
font-weight:bold;
text-align:center;
vertical-align:middle;
}
.d_top span{
float:left;
font-size:13px;
margin-left:15px;
margin-top:8px;

}
.d_body {
BORDER-RIGHT: #5cc 3px solid;
BORDER-LEFT: #5cc 3px solid;
padding:10px;
height:200px;
background-color:#fff;
}
.d_foot{
clear:both;
overflow:hidden;
background-color:#5cc;
height:2px;
}
</style>
<script type="text/javascript">
function $(id){return document.getElementById(id);}
function show(id){
var t = $(id);
t.style.width=document.body.clientWidth;
t.style.height=document.body.clientHeight;
window.onresize=function(){
t.style.width=document.body.clientWidth;
t.style.height=document.body.clientHeight;
}
$(id).style.display="";
}
function cl(id){
$(id).style.display="none";
}

function moveEvent(e,id){
var isIE = (document.all)?true:false;
drag = true;
xx=isIE?event.x:e.pageX;
yy=isIE?event.y:e.pageY;
L = document.getElementById(id).offsetLeft;
T = document.getElementById(id).offsetTop;
document.onmousemove = function(e) {
if (drag) {
x=isIE?event.x:e.pageX; if(x<0)x=0;
y=isIE?event.y:e.pageY; if(y<0)y=0;
document.getElementById(id).style.left = L-xx+x;
document.getElementById(id).style.top = T-yy+y;
}
}
document.onmouseup=function(){
drag = false;
}
}
window.onscroll=function(){
$("back_div").style.width=document.body.scrollWidth;
$("back_div").style.height=document.body.scrollHeight;
}
</script>
<body>
<div ></U>
</DIV>
</div>
</body>