Need some advice, best way to create a simple bar graph...

Ok, I am attempting to create a bar graph like this...

http://jyte.com/cl/i-dig-anime

if you scroll a tiny bit down the page you will see it. Now I looked at it and it just looks like a simple image that is altered. I was thinking of possibly using some javascript to achieve this. Does anyone have any ideas? Any suggestions are greatly appreciated.

It looks like the javascript dynamically alters the style percentage of the green and red bars respectively so that when a vote is cast the script reads whichever way it went, works out the percentages and then changes the style of the green and red bar accordingly. However, don't ask me how it's done because my javascript knowledge is very limited. View the source and navigate to the js file to get some ideas if know js.