This script is excellent for testing page background and font colors together. It provides the hexadecimal numbers for the colors too.
The JavaScript Source: Miscellaneous: Compare Colors
Simply click inside the window below, use your cursor to highlight the script, and copy (type Control-c or Apple-c) the script into a new file in your text editor (such as Note Pad or Simple Text) and save (Control-s or Command-s). The script is yours!!!