[jQuery] How to make hyperlink failed

[jQuery] How to make hyperlink failed


If I got a hyperlink <a href="http://xxx.com" id="xxx">xxx</a>
$(function() {
    $('#xxx').click(function() {
    .........
    ......//do something
    });
})
I want to make the link doing something if browser opened javascript,
and if not, it go to the page it referred.