The WordCounter.net add-on for Firefox will help you count both words and characters quickly and easily. Once the add-on is added to Firefox, you will be able to keep track of your typed out words with just a click of the mouse. This is all powered by the very helpful services at WordCounter.net too.
Here is a little more about this add-on:
Wordcounter is a word count and a character count tool. Simply place your cursor into the box and begin typing. Word counter will automatically count the number of words and characters as you type. Word Counter now also counts keyword density.
Love the idea of this add-on? Check it out on the Firefox Add-ons website.