Help: Program Flow When Error In Onclick Event?

what happens when you have an onclick event and an error occurs in it:

In an <a> element:
onclick="zoomFullExtent(); return false;"

I know that there is an error happening in zoomFullExtent. I didn't
define my own error handler, so the default one is used.(My browser is
Firefox 1.0).

I notice that when this error happens, the browser makes a request to
the server.

I thought that if an error happened in zoomFullExtent, the default
error handler would catch it, and then zoomFullExtent would return
normally. But that doesn't seem to happen. Instead the whole onclick
script returns or is aborted? And it seems to return true so that the
request is made. Is there a page where this program flow is explained?