CascadingDropDown options is null or not an object

I have a couple of dropdown CascadingDropDown and the user is required to select an option from the first and then the second, and then click add. However, if they press add to fast, I get the error "'options' is null or not an object"

It's as if the the second dropdown is not full before the event is posted?!?!? Anyone know how I can prevent this?

Hi Poidda,

Based on my experience, to resolve this kind of issue we should make sure whether the problem is occurred on the client side or on the server side. Based on your description, I think your problem is likely occurred on the server side.

If it is a client issue, we suggest that you should keep the Button to be disabled until the last essential CascadingDropDown is selected. For example:

function pageLoad(){
$find("myCDEState").add_selectionChanged(onCCDSelected)
}
function onCCDSelected(){
//your other javascript code here.

$get("<%=Button.ClientID%>").disabled = false;
}

Otherwise , you should do some checking work on the server side. If it's null, return to the orignal page.

Best regards,

Jonathan