function popup(url_address,window_width,window_height,scroll) {
	x = (screen.availWidth-window_width)/2;
  y = (screen.availHeight-window_height)/2;
	p = 'width='+window_width+',height='+window_height+',Left='+x+',Top='+y+',screenX='+x+',screenY='+y;
	if(scroll=="no") p += ',scrollbars=no';
	else p += ',scrollbars=yes';
  FromWindow = window.open(url_address, 'NewWindow', p);
	FromWindow.focus();
	return FromWindow;
}