Clear URL bar on tab load

I am writing a Firefox addon and it opens a page in the addon instead of the blank page for a new tab, but it has the U开发者_如何学编程RL in the url bar which I would like to be empty. How do I clear the url bar?

For example, is it something like: gURLBar.clear();

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Figured out my problem, I just use this: gURLBar.value = "";