Hello friend....
you have to do this using javascript.. like this...
<html>
<head>
<title></title>
<style type="text/css">
.div
{
color: #FF0000;
border-color: #FF0000;
}
</style>
<script type="text/javascript">
function add() {
var container = document.getElementById("test");
var chekc = document.createElement("input");
chekc.type = "checkbox";
chekc.id = "c1";
chekc.value = "234";
var lable = document.createElement("label");
lable.htmlFor = "c1";
lable.appendChild(document.createTextNode('label'));
container.appendChild(chekc);
container.appendChild(lable);
}
</script>
</head>
<body>
<form>
<input type="button" value="Add Check Box" id="btn" onclick="add();" />
<div id="test" class="div">
</div>
</form>
</body>
</html>
Like this it is for only html but you can do it for asp.net check box also this is only for hint....
This will work for you...!!!!!