//global variables that can be used by ALL the function son this page.
var inputs;
var imgFalse = 'images/checkbox_normal.png';
var imgTrue = 'images/checkbox_highlight.png';
//this function runs when the page is loaded, put all your other onload stuff in here too.

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') == 'radio') {
			//create a new image
			var img = document.createElement('img');
			//check if the checkbox is checked
			inputs[i].checked = false;
			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) {
		inputs[i].checked = 'checked';
		document.getElementById('checkImage'+i).src=imgTrue;
		
		if(document.getElementById('checkImage'+eval(i+1)))
		{
			inputs[eval(i+1)].checked = 'checked';
			document.getElementById('checkImage'+eval(i+1)).src=imgFalse;
		}
		
		if(document.getElementById('checkImage'+eval(i-1)))
		{
			inputs[eval(i-1)].checked = 'checked';
			document.getElementById('checkImage'+eval(i-1)).src=imgFalse;
		}
}