function op(p_url, p_width, p_height, p_scroll) {
	var p = ",left=200,top=100,resizable=yes";
	var w = (p_width)  ? p_width  : 940;
	var h = (p_height) ? p_height : 580;
	var x = Math.round((window.screen.availWidth  - w) / 2);
	var y = Math.round((window.screen.availHeight - h) / 2) - 20;;
	if (p_scroll === false) p = p + ",scrollbars=no"; else p = p + ",scrollbars=yes";
	pw = window.open(p_url, "pw", "width=" + w + ", height=" + h + ", screenX=" + x + ", screenY=" + y + p);
	pw.focus();
};