function openwin(url,title,width,height)
{

var x = 0;
var y = 0;
winWidth = width;
winHeight = height;
x = (screen.availWidth - 12 - winWidth) / 2;
y = (screen.availHeight - 48 - winHeight) / 2;

var text = 'width='+winWidth+',height='+winHeight+',top='+y+',left='+x+',directories=no,location=no,menubar=no,scrollbars=yes,status=no,toolbar=no,resizable=yes';
var title = "flashfilechoser";
var NewWindow = window.open(url,title,text);  

}