Thanks - heres what I have come up with which seems to work for small tables but as when I apply it to say a 30 column x 50 row table the script becomes unresponsive.

Heres what its supposed to do:

Onmouseover, if the cell is white, and so are the required number of cells below it then it will turn them green, and back to white on mouse out.

If any of the cells in the required block are orange, then it...

Many thanks - but can you explain how I use this in more detail please. Im still learning javascript. Would I need to integrate this into the function that does the highlighting? Would I need this to run once or everytime I moused over a cell in the table (so that it calculates the correct cellindexes before going on to highlight the cell and the required number of cells below it)?...

Is there a way to determine the correct cellindex of cells in a table when some of the cells have rowspans greater than 1. Perhaps correct is the wrong word - but when I have a cell with a rowspan greater than one, the cellindex of the the cells to its right and one row down are 1 less than I expect.

This is causing my cell highlight function to behave incorectly as instead of highlighting say 3 cells in a column, it highlights the...