Sometimes people are confused about the "return false" in an onClick handler. Essentially, the browser is asking your event handler code a true/false question: should I do what I normally do when this event occurs? For a hyperlink, the normal thing to do is to go to the given HREF location, so by returning false, you're saying "no, don't go there."
Here are some examples. The link describes how the code behaves, but feel free to "view source" to see the code.
this link would go to # but the onClick handler returns false
this link goes to # (this same page) and the onClick handler returns true
this link goes to # (this same page) and the onClick handler returns false
this link opens the Wellesley home page in a new window, but doesn't return false.