// 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 {
	alert("Error: Please select a choice.");
	return false;
	}
}