//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = 'none.png';
var imgTrue = 'none.png';

var flag = -1;

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

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') {
			
			// record the index of the first checkbox
			if (flag==-1) {
				flag = i;
			}
			
			//create a new image
			var img = document.createElement('img');
			
			// If this is the first checkbox, set the appropriate images
			if (i==flag){
				imgFalse = 'orange-tick.gif';
				imgTrue = 'orange-ticked.gif';
			} else {
				imgFalse = 'green-tick.gif';
				imgTrue = 'green-ticked.gif';
			}
			
			//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';
		}
	}
}

//change the checkbox status and the replacement image
function checkChange(i) {
	
	// If this is the first checkbox, set the appropriate images
	if (i==flag){
		imgFalse = 'orange-tick.gif';
		imgTrue = 'orange-ticked.gif';
	} else {
		imgFalse = 'green-tick.gif';
		imgTrue = 'green-ticked.gif';
	}

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

//window.onload = init;