// Radio Button Validation
	// copyright Stephen Chapman, 15th Nov 2004,14th Sep 2005
	// you may copy this function but please keep the copyright notice with it
	function valButton(btn) {
	    var cnt = -1;
	    for (var i=btn.length-1; i > -1; i--) {
	        if (btn[i].checked) {cnt = i; i = -1;}
	    }
	    if (cnt > -1) return btn[cnt].value;
	    else return null;
	}