I'm not sure which programming language would be good for this project so I just chose a few that you can pick from.
Here's exactly what I need done:
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This is an add-on in order to help select a category on websites. It loads the list of categories from the website into the add-on to make it easier to see and select a category. When you select a category it will change it on the website within the tab that you're on. If you double click the category, it will add it to the "Auto" list. The auto list simply automatically tries to select an appropriate category from the list as soon as you visit webpages. Double clicking an item in the "Auto" list will remove it. The "Next" button will search the category list again for the next suitable category by using the categories in the "Auto" list.
It should work in the browser Internet Explorer 7.