Untitled

<html>
	<head>
		<title>Toggle</title>
	</head>
<body>
<script>
var classes = ["cam","cam1","cam2"]
currentstate = 0
nextstate=currentstate+1
function toggle(){
if (currentstate == classes[2]){
nextstate = classes[0]
}
else{

cam = document.getElementById("cam")
cam.innerHTML=currentstate;
currentstate = classes[currentstate+1]

}
}
</script>
<input type="button" value="Click Here" onclick="toggle()" />
<div id="cam">
test
</div>
</body>
</html>