In the table on that page, move your mouse over the cells. Notice how they change color when the mouse is on them, and the color goes away when you move the mouse to another cell.
Now, using Firefox or Chrome (but not IE, Opera, etc.), I want to examine the background color, expressed in RGB or hex or whatever, of the cells updated in real time, as the mouse cursor enters and leaves the region and causes the JS to do its thing.
If it is possible to have the values updated in real time using either Firefox or Chrome, or an extension, on any recent version of the software (up to the latest stable), please provide instructions for doing so.