function open_venster(pad,naam,breed,hoog) {
	venster = window.open(pad, naam, "width=" + breed + ",height=" + hoog +
	",toolbar=no,location=no,directories=no,status=0,resizable=no,scrollbars=no,menubar=no");
	venster.moveTo(((screen.width/2)-(breed/2)),((screen.height/2)-(hoog/2)));
}

function popup()
{
	open_venster("/page/registratie/","registratie",400,600);
}