Onchange is not a function

Please follow the instructions below to troubleshoot the “onchange is not a function” error:

The “onchange is not a function” error typically occurs when you are trying to use the “onchange” event on an element that does not support this event or when the function you are referring to does not exist.

Possible Causes and Solutions:

1. Incorrect element: Ensure that you are applying the “onchange” event to the appropriate HTML element. The “onchange” event is typically used with form inputs like select drop-downs, checkboxes, or radio buttons. For example, this code snippet assigns the onchange event handler to a select element:

   <select onchange="myFunction()">
     <option value="1">Option 1</option>
     <option value="2">Option 2</option>
   </select>

2. Function not defined: Make sure that the function referenced in the “onchange” attribute is defined in your JavaScript code. Here’s an example of defining a function named “myFunction” in a script tag:

   <script>
     function myFunction() {
       // your code here
     }
   </script>

3. Scope issues: Check if the function is defined within the correct scope or if there are any conflicts with other variables or functions. For instance, if you have multiple JavaScript libraries on your page, they might conflict with each other and cause the “onchange is not a function” error.
4. Script loading order: Ensure that the JavaScript code containing the function is loaded before the element with the “onchange” attribute. This is important because if the event is triggered before the function is loaded, the error can occur. You can achieve this by placing the script tag that defines the function before the element or by using the “defer” attribute on your script tag.

By analyzing the potential causes mentioned above and making the necessary adjustments, you can resolve the “onchange is not a function” error and make the event work correctly.