>>>>var myElement = ...
>>>>if (myElement!=null)
>>>> ....
>>>>
>>>>It is explained in the link.
>>>
>>>Thank you. Sorry, somehow I didn't see the link in the initial reply. I must be losing my mind.
>>
>>I actually added it with Update, so may be you didn't see it when you first opened my reply.
>
>Strange is that the var value is NOT null. But I can't get the .value of it. Even though the HTML code has value="123456". I must be missing something.

Can you show your exact new code? Is it a hidden input? Did you also try text property?