.mydiv {
background-image: url(/Public/images/xcxc.jpg); font-size:13px;
background-repeat: no-repeat;
background-position: top center;
background-size: cover;
text-align: center;
z-index:1000;
width: 50%;
height: 80%;
left:25%;/*FF IE7*/
top: 10%;/*FF IE7*/
box-shadow: 5px 5px 10px #333;
-webkit-box-shadow: 5px 5px 10px #333;
-moz-box-shadow: 5px 5px 10px #333; border: 1px solid #ccc;
border-radius: 6px;
-webkit-border-radius: 6px;
-moz-border-radius: 6px;

position:fixed!important;/*FF IE7*/
position:absolute;/*IE6*/

_top: expression(eval(document.compatMode &&
document.compatMode=='CSS1Compat') ?
documentElement.scrollTop + (document.documentElement.clientHeight-this.offsetHeight)/2 :/*IE6*/
document.body.scrollTop + (document.body.clientHeight - this.clientHeight)/2);/*IE5 IE5.5*/

}
.closediv{width: 26px;height: 26px; right: -12px; top: -12px; position: absolute;
          background: url(/Public/images/close.png) no-repeat; cursor: pointer;
}

.popbg {
background-color: #000;
width: 100%;
height: 100%;
left:0;
top:0;/*FF IE7*/
filter:alpha(opacity=30);/*IE*/
opacity:0.3;/*FF*/
z-index:999;

position:fixed!important;/*FF IE7*/
position:absolute;/*IE6*/

_top: expression(eval(document.compatMode &&
document.compatMode=='CSS1Compat') ?
documentElement.scrollTop + (document.documentElement.clientHeight-this.offsetHeight)/2 :/*IE6*/
document.body.scrollTop + (document.body.clientHeight - this.clientHeight)/2);/*IE5 IE5.5*/

}