onchange javascript w3schools code example
Example 1: onchange js
<script>
document.getElementById("fname").addEventListener("change", myFunction);
function myFunction() {
var x = document.getElementById("fname");
x.value = x.value.toUpperCase();
}
</script>
Example 2: js html textbox on change
<!--
You can use any of the following:
onkeydown, onkeyup or onchange
-->
<input type="text" onkeydown="keydownFunction()"
onkeyup="keyupFunction()" onchange="changeFunction()">