function open_messenger(pageUrl)
{	
	var pageUrl, attributes;
	var popup_width, popup_height, screen_width, screen_height, popup_left, popup_top;
	screen_width = window.screen.width;
	screen_height = window.screen.height;
	popup_width = 400;
	popup_height = 400;
	popup_left = Math.round((screen_width-popup_width)/2);
	popup_top = Math.round((screen_height-popup_height)/2);    
	attributes = "scrollbars=0,resizable=0,toolbar=0,location=0,directories=0,status=0,menubar=0,height=" + popup_height + ",width=" + popup_width + ",top="+popup_top+",left=" + popup_left; 
	window.open(pageUrl,'',attributes);
}