javascript onchange code example

Example 1: onchange on select tag

<select id="comboA" onchange="getComboA(this)">
  <option value="">Select combo</option>
  <option value="Value1">Text1</option>
  <option value="Value2">Text2</option>
  <option value="Value3">Text3</option>
</select>

Example 2: onchange js

<script>
document.getElementById("fname").addEventListener("change", myFunction);

function myFunction() {
  var x = document.getElementById("fname");
  x.value = x.value.toUpperCase();
}
</script>

Example 3: js select on change value

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

Example 4: 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()">

Example 5: javascript input onchange get value

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