Uncaught TypeError While Attaching Client Side Event to Telerik RadEditor

In this Blog, we will explore the error I faced, while I was attaching Events to Telerik RadEditor and how I resolved that.


Declare the Event in Markup

We need to declare RadEditor OnClientLoad Event for the RadEditor.

This event is fired after the content is set in the content area, after the OnClientInit event and just before the editor is ready for use.


Define the Event

We are going to attach onkeydown, onchange and onpaste Events to the RadEditor. So, whenever we type or paste something in the RadEditor, detectChanges() will be fired.

function OnClientLoad(editor)
    editor.attachEvent('onkeydown', function(){ detectChanges(); });
    editor.attachEvent('onchange', function(){ detectChanges(); });
    editor.attachEvent('onpaste', function(){ detectChanges(); });

function detectChanges()
    alert("You are doing something in RadEditor !!!");

Let’s Test

Let’s type or paste something in the RadEditor now.

OOPS !!!! Something bad happened. The below is what I see in the Chrome Developer Tool Browser Console.

RadEditor Error

RadEditor Error

What to do now?

Now, the error message says “Uncaught TypeError : undefined is not a function OnClientLoad“. That means, the way we are attaching the Events, is wrong.
So, I looked back to where I started and suddenly I saw that we should attach the Event with attachEventHandler instead of attachEvent. Moreover, attachEvent is no longer supported as MSDN indicated.

Therefore, the updated working code will be…

function OnClientLoad(editor)
    editor.attachEventHandler('onkeydown', function(){ detectChanges(); });
    editor.attachEventHandler('onchange', function(){ detectChanges(); });
    editor.attachEventHandler('onpaste', function(){ detectChanges(); });

function detectChanges()
    alert("You are doing something in RadEditor !!!");

Final correct Output

Here is the alert box, which opens when we type something in the RadEditor.

RadEditor onkeydown Event

RadEditor onkeydown Event

End Notes

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