shown=''
function OpenFile(url,width,height) {

var Left = (screen.width - width) / 2 - 5;
var Top = (screen.height - height) / 2 - 29;

if( shown=='' || shown.closed) {

window.focus();
shown=window.open(url,"OpenFile","top="+Top+",left="+Left+",width="+width+",height="+height+",scrollbars=yes,status=no,high");

}
else{
shown.close();
shown=window.open(url,"OpenFile","top="+Top+",left="+Left+",width="+width+",height="+height+",scrollbars=yes,status=no,high");
}
}