JavaScript onchange Event Example

Updated on January 4, 2016     Kisan Patel

If we want to execute a javascript function when the element value is changing, we need to use javascript onchange event

<!-- HTML -->
Name: <input type="text" name="txtName" id="txtName" onchange="TestFunction(this.id)" />
<br/>
<label id="lblName"></label>

<!-- Javascript -->
<script type="text/javascript">
function TestFunction(id) {
   document.getElementById("lblName").innerHTML = document.getElementById(id).value;;
}
</script>

In the above code snippet, we have a textbox on which onchange event has been specified that executes TestFunction() function. In this function we are setting the Label (lblText) inner html value to the textbox value.