<!DOCTYPE html>
<html>
<body>
<p>This example uses the HTML DOM to assign an "onkeyup" event to an input element.</p>
<p>Press a key inside the text field and release it to set the text to uppercase.</p>
Enter your name: <input type="text" id="fname">
<script>
document.getElementById("fname").onkeyup = function() {myFunction()};
function myFunction() {
var x = document.getElementById("fname");
x.value = x.value.toUpperCase();
}
</script>
</body>
</html>