<html>
<head>
<script>
function convertToUcase()
{
document.getElementById("fname").value=document.getElementById("fname").value.toUpperCase();
}
</script>
</head>
<body>
<form name="form1">
First name: <input type="text" id="fname" size="20" value="Donald Duck">
<br><br>
Convert to upper case
<input type="checkBox" onclick="if(this.checked){convertToUcase()}">
</form>
</body>
</html>