<!DOCTYPE html>
<html>
<body>
<p>Modify the text in the input field, then click outside the field to fire the onchange event.</p>
Enter some text: <input type="text" name="txt" value="Hello" onchange="myFunction(this.value)">
<script>
function myFunction(val) {
alert("The input value has changed. The new value is: " + val);
}
</script>
</body>
</html>