var total_correct = 0;
var fg_color = '#ff0000';
var bg_color = '#ffff00';

function check_answer_q(id, rbAnswer, answer) {
	//alert(rbAnswer[answer]);

	var correct = false;
	if(rbAnswer[answer].checked) {
		correct = true;
	}
	//alert(correct);

	if(correct) {
		img = 'images/answer_correct.jpg';
		total_correct++;
	} else {
		img = 'images/answer_wrong.jpg';
	}
	document.images['answer_result' + id].src = img;

	if (document.layers) {
		window.document.layers['correct' + id].color = fg_color;
		window.document.layers['correct' + id].bgColor = bg_color;
	} else if (document.all) {
		window.document.all['correct' + id].style.color = fg_color;
		window.document.all['correct' + id].style.background = bg_color;
	}	
}

function check_answer() {
	//alert('check_answer');

	var len = document.images['submit'].src.length;
	if(document.images['submit'].src.substring(len - 8) == 'back.jpg') {
		history.back();
		return true;
	}

	var r = confirm("Are you sure you want to submit now?")
	if(r == true) {
		check_answer_q(1, document.forms.form.Answer1, 3);
		check_answer_q(2, document.forms.form.Answer2, 0);
		check_answer_q(3, document.forms.form.Answer3, 3);
		check_answer_q(4, document.forms.form.Answer4, 1);
		check_answer_q(5, document.forms.form.Answer5, 3);
		check_answer_q(6, document.forms.form.Answer6, 0);
		check_answer_q(7, document.forms.form.Answer7, 3);
		check_answer_q(8, document.forms.form.Answer8, 2);
		check_answer_q(9, document.forms.form.Answer9, 0);
		check_answer_q(10, document.forms.form.Answer10, 2);

		//alert(total_correct);
		document.all("result1").innerText = 'Result:';
		document.all("result2").innerText = total_correct + ' correct out of 10';
		//document.all("submit").innerText = '';
		location.href = '#';

		document.images['submit'].src = 'images/QuestionPage/back.jpg';
		
		return true;
	} else {
		return false;
	}
}

function disableSelection(element) {
	element.onselectstart = function() {
		return false;
	};
	element.unselectable = "on";
	element.style.MozUserSelect = "none";
	element.style.cursor = "default";
}
function prompt_register(){
	alert("Please register on 7 May!");
}

function prompt_activate(){
	alert("You can read about this topic and do the exercises on 28 March.");
}