title: How to write a button firefox add-on
body: <p>I'm experimenting with a firefox plugin, but I'm new to this and wouldn't mind a little push. If I wanted to write a simple plugin that's nothing but a button and when the button is clicked, it displays an alert message like "hello" or something. How would the js for this add-on look like?</p>
  
  <p>Edit: I'm also thinking, it probably doesn't have to be a button as in a toolbar button, probably just a button that appears somewhere on a page and can be activated. But not sure if there's any disadvantages to this method over using an actual toolbar button.</p>