var startQ, endQ;

/**
 * check that all the questions have been answered before submitting
 **/ 
function checkSubmit(part) {
	if (part == 1) {
		startQ = 1; endQ = 20;
	} else if (part == 2) {
		startQ = 21; endQ = 40;
	} else if (part == 3) {
		startQ = 41; endQ = 60;
	} else if (part == 4) {
		startQ = 61; endQ = 80;
	}
	var theForm = document.forms[0];
	if (part == 5) {
		startQ = 81; endQ = 86;
		var val1 = eval("theForm.Q86[0].checked");
		var val2 = eval("theForm.Q86[1].checked");
		var val3 = eval("theForm.Q86[2].checked");
		var val4 = eval("theForm.Q86[3].checked");
		var val5 = eval("theForm.Q86[4].checked");
		if (val1 == false && val2 == false && val3 == false && val4 == false && val5 == false) {
			alert("Please answer all questions before continuing.");
			return false;
		}
		if (theForm.Q81.selectedIndex < 0 || theForm.Q83.value == "" || theForm.Q84.selectedIndex < 0 || theForm.Q85.value == "") {
			alert("Please answer all questions before continuing.");
			return false;
		}
	} else if (part == 1) {
		var form = document.forms[0];
		// check first part of the form
		if (form.name.value == "" || form.age.value == "" || form.city.value == ""
			|| form.state.value == "" || form.country.value == "" || form.majcity.value == "" || form.race.value == ""
			|| (form.sex[0].checked == false && form.sex[1].checked == false)) {
			alert("Please fill all your personal details");
			return false;
		} else if (form.email.value == "" || form.email.value.indexOf("@") == -1) {
			alert("Please fill in your valid email address");
			return false;
		}
		// check answers
		for (i = startQ; i <= endQ; i++) {
			var val1 = eval("theForm.Q" + i + "[0].checked");
			var val2 = eval("theForm.Q" + i + "[1].checked");
			var val3 = eval("theForm.Q" + i + "[2].checked");
			if (val1 == false && val2 == false &&  val3 == false) {
				alert("Please answer all the questions before continuing.");
				return false;
			}
		}
	}else {
		for (i = startQ; i <= endQ; i++) {
			var val1 = eval("theForm.Q" + i + "[0].checked");
			var val2 = eval("theForm.Q" + i + "[1].checked");
			var val3 = eval("theForm.Q" + i + "[2].checked");
			if (val1 == false && val2 == false &&  val3 == false) {
				alert("Please answer all the questions before continuing.");
				return false;
			}
		}
	}
	return true;
}