p{ margin:0px; padding:0px;}
.mydiv {
background-color:Black;

text-align: center;
line-height:30px;
font-size: 12px;
font-weight: bold;
z-index:999;
width:580px;
height:auto;
 padding-bottom:20px;
left:40%;/*FF IE7*/
top:18%;/*FF IE7*/
margin-left:-150px!important;/*FF IE7 该值为本身宽的一半 */
margin-top:-60px!important;/*FF IE7 该值为本身高的一半*/
margin-top:0px;
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*/
}
.bg,.popIframe {
background-color: #666; display:none;
width: 100%;
height: 100%;
left:0;
top:0;/*FF IE7*/
filter:alpha(opacity=50);/*IE*/
opacity:0.5;/*FF*/
z-index:1;
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*/
}
.popIframe {
filter:alpha(opacity=0);/*IE*/
opacity:0;/*FF*/
}