function centering(pw,cw) {
	return (pw-cw)/2;
}
function openSUB(url) {
	var obj = getElement("frmSUB");

	obj.src = url;

	setVisibility(obj,true);

	var x = document.body.scrollLeft + centering(getWindowWidth(), getWidth(obj));
	var y = document.body.scrollTop  + centering(getWindowHeight(),getHeight(obj));
	setLeft(obj,x);
	setTop(obj,y);
}