preventDefault won't work on Firefox

I'm trying to prevent A HREF from actually opening the link, but to execute a script. I got the script part working, but it seems Firefox would just ignore this:

$("#permalink a").click(function(id){
  $("#newPost").fadeToggle;
  event.preventDefault();
  var id = this.getAttribute('href');
  $("#newPostContent").load(id);
  $("#newPost").show("fast");
});

Can anyone suggest a cross-browser script for preventing defaults?