function openPopup(mylink, windowname, width, height) {

	var	screenX = window.screen.width;
	var screenY = window.screen.height
	var left = ( screenX /2 ) - (width/2) - 100 ;
	var top = ( screenY /2 ) - (height/2) - 100 ;

	var props = 'height='+height+',width='+width+',left='+left+',top='+top+',scrollbars=yes' ;

	var href;
	if (typeof(mylink) == 'string'){
	   href=mylink;
	} else {
   		href=mylink.href;
	}
	var newwindow=window.open(href, windowname , props);
}

function closePopup(){
	window.close();
}