function center(width,height,cx,cy){
	var x=(cx==0)?0:(cx==1)?parseInt((screen.width-width-10)/2):screen.width-width-10;
	var y=(cy==0)?0:(cy==1)?parseInt((screen.height-height-56)/2):screen.height-height-56;
	return (",top="+y+",left="+x);
}
function openwindow(url){ window.open(url,"registrera_pop","toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,width=787,height=515"+center(787,515,1,1)+""); }