set innerHTML within grid, value disappears in Firefox

I have data within a grid.
I have a span set within that datacell.
I go to change the innerHTML becuase I need to do custom caluculations and the data disappears. It works in IE.

Yes, I saw something similar in FF. The text is there but FF just does not display it. Try to refresh the whole cell instead of just text innerHTML.

How can I refresh the entire cell when I am in my custom Javascript function?