javascript: check if element can accept a value

I am trying to do something like this (pseudo-code):

if ( element can accept a value )
    element.value = "my new value";
else
    element.innerHTML = "my new value";

So for input, textarea, etc it will set the value, but for div or span it will set the innerHTML.

Or should I simply set both value and innerHTML, since innerHTML is harmless to set for input elements?