onchange function in javascript 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 select on change value
document.getElementById('my-select').addEventListener('change', function() {
console.log('You selected: ', this.value);
});