Updating the cell Text of a grid

I have a grid in place right now, and want to update the data in the cells only. The complication comes because the number of rows can change between updates. If I just form a new javascript array, redefine rowCount, set cell text with it and refresh, will this work properly? There seems to be some problem in my code, is it overlapping or something?
If so, is there a way to just clear the cells or the cell text from the grid, and then just set the new cell text to the new array? Thanks