onchange event 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);
});

Example 3: javascript input onchange get value

var element = document.getElementById("myInput");
element.onchange = function() {
  console.log(element.value);
}

Example 4: javascript add function to onchange event

transport_select.setAttribute("onchange", function(){toggleSelect(transport_select_id);});
// or
transport_select.onchange = function(){toggleSelect(transport_select_id);};