I'm using the next CSS:
.table {
    position:static;
    width: 300px;
    height: 300px;
    margin-left: auto;
    margin-right: auto;
    left:0;
    right:0;
}
Obviously I used them where they belong. But I also added some script in other page:
<script language="javascript">
    var left = (screen.width/2)-(300/2);
    var top = (screen.height/2)-(300/2);
    window.open('page.aspx?' + window.location.href.toString().split('?')[1], 'PopUp', 'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=no, resizable=no, copyhistory=no, width=300, height=300, top=' + top + ', left=' + left);
    window.open('', '_self').close(); 
</script>
All what I wanted for many hours, was to be in the correct position, no white line between top and left. And I don't realize what else I have to do.
Help is always welcome.