function openwindow(url)
{
    var url;                             
    var name = "newwindow"; 
    var iWidth = 600; 
    var iHeight = 450;
    var iTop = (window.screen.availHeight-30-iHeight)/2;        
    var iLeft = (window.screen.availWidth-10-iWidth)/2;           
    window.open(url,name,'height='+iHeight+',innerHeight='+iHeight+',width='+iWidth+',innerWidth='+iWidth+',top='+iTop+',left='+iLeft+',status=no,toolbar=no,menubar=no,location=no,directories=no,resizable=yes,scrollbars=no,titlebar=no');
}