function NumOnly() {
	var el, key;
	el = window.event.srcElement;
	
	if (el.tagName == "INPUT") {
		key = window.event.keyCode;
		if ((key < 48) || (key > 57)) { //Povoli se pouze "0" (48) až "9" (57)
			window.event.returnValue = false;
		};
		window.event.cancelBubble = true;
	};
};