//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = 'resources/themes/oa/images/check0.gif';
var imgTrue = 'resources/themes/oa/images/check2.gif';

//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') {
			
			if (inputs[i].style.display != 'none') {
				
				if (!inputs[i].disabled) {
					//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;
					}
					
					img.className='oacheckbox';
		
					//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(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;