[jQuery] simple browser check (need help)

I have a tool that only operates under IE

So all other browser users get an alert here is my code...but it
doesn't work...

Can someone get me straightened out?

<script>
$(document).ready(function()
        {
        if($.browser.[safari, opera, mozilla])
                {
                        $( function() { alert("You must use Internet Explorer 
to view the
links at this time!");
                }
        );
        }
);
</script>