function window_open(fname, w, h) {
x='';
l=(screen.width-w)/2;
t=(screen.height-h)/2;
mywindow=window.open(fname,x,'width='+w+',height='+h+',toolbar=0,scrollbars=0,menubar=0,location=0,left='+l+',top='+t+',status=0,resizable=1');
}