//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = 'resources/images/checkbox.png';
var imgTrue = 'resources/images/checkbox_checked.png';

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

function replaceChecks(mode) {

	//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
			if (mode == 'radioButton') 
			{
				img.onclick = new Function('radiobuttonChange(' + i + ')');
			}
			else 
			{
				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';
		}
	}
}

//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;
		}
}

//change the radioButton status and the replacement image
function radiobuttonChange(index)
{
	for (var i = 0; i < inputs.length; i++) 
	{
		if (document.getElementById('checkImage' + i) != null) 
		{
			if (i == index) 
			{
				inputs[i].checked = 'checked';
				document.getElementById('checkImage' + i).src = imgTrue;
			}
			else 
			{
				inputs[i].checked = '';
				document.getElementById('checkImage' + i).src = imgFalse;
			}
		}
	}
}