You opened the "height" can of worms, and now the only way to recan them is to get a bigger can.

First of all, whether the getElementById gets the correct value depends on how that value got there.

- The value is available if it got there through rendering of the original web page, or if it was set by the JavaScript program.

- A former value is returned if some dynamic content other than the JavaScript changed the attribute. An example is a div resizing itself to hold an object that was not loaded when the original page was rendered.