//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = 'http://i.investopedia.com/inv/quizzer/false.jpg';
var imgTrue = 'http://i.investopedia.com/inv/quizzer/true.jpg';

var imgRadioFalse = 'http://i.investopedia.com/inv/quizzer/rfalse.jpg';
var imgRadioTrue = 'http://i.investopedia.com/inv/quizzer/rtrue.jpg';

//this function runs when the page is loaded, put all your other onload stuff in here too.
function init() {
	replaceChecks();
}

function replaceChecks() {
	
	//get all the input fields on the page
	inputs = document.getElementsByTagName('input');

	//cycle trough the input fields
	for(var i=0; i < inputs.length; i++) {

		//check if the input is a checkbox
		if(inputs[i].getAttribute('type') == 'checkbox') {
			
			//create a new image
			var img = document.createElement('img');
			
			//check if the checkbox is checked
			if(inputs[i].checked) {
				img.src = imgTrue;
			} else {
				img.src = imgFalse;
			}

			//set image ID and onclick action
			img.id = 'checkImage'+i;
			//set image 
			img.onclick = new Function('checkChange('+i+')');
			//place image in front of the checkbox
			inputs[i].parentNode.insertBefore(img, inputs[i]);
			
			//hide the checkbox
			inputs[i].style.display='none';
		}
	}
	
	/*//cycle trough the input fields
	for(var k=0; k < inputs.length; k++) {

		//check if the input is a radio
		if(inputs[k].getAttribute('type') == 'radio') {
			
			//create a new image
			var img = document.createElement('img');
			
			//check if the radio is checked
			if(inputs[k].checked) {
				img.src = imgRadioTrue;
			} else {
				img.src = imgRadioFalse;
			}

			//set image ID and onclick action
			img.id = 'checkImage'+k;
			//set image 
			img.onclick = new Function('checkChange('+k+')');
			//place image in front of the checkbox
			inputs[k].parentNode.insertBefore(img, inputs[k]);
			
			//hide the checkbox
			inputs[k].style.display='none';
		}
	}*/
}

//change the checkbox status and the replacement image
function checkChange(i) {

	if(inputs[i].checked) {
		inputs[i].checked = '';
		document.getElementById('checkImage'+i).src=imgFalse;
	} else {
		inputs[i].checked = 'checked';
		document.getElementById('checkImage'+i).src=imgTrue;
	}
}

/*function checkChange(k) {

	if(inputs[k].checked) {
		inputs[k].checked = '';
		document.getElementById('checkImage'+k).src=imgRadioFalse;
	} else {
		inputs[k].checked = 'checked';
		document.getElementById('checkImage'+k).src=imgRadioTrue;
	}
}*/

window.onload = init;