function isRadioSelected(elementName) {

	var targets = $A(document.getElementsByName(elementName));
	if (targets == undefined)	{
		targets = $A([]);
	}
	return targets.find(function(v) { return v.checked });
}

function validateRequired() {

	var valid = true;
	for(var questionIndex = 0; questionIndex < 20; questionIndex++) {

		var radioName = "Q" + questionIndex;
		var warningID = "warning_Q" + questionIndex;

		if ($(warningID) == undefined) {
			continue;
		}

		if (isRadioSelected(radioName) != undefined) {
			$(warningID).hide();
		} else {
			$(warningID).show();
			valid = false;
		}
	}
	if (valid) {
			$("warning_explanation").hide();
	} else {
			$("warning_explanation").show();
			location.href = "#warning_explanation";
	}

	return valid;
}