About html link tag <a>'s HREF

1.adds # to the browser url and jumps to the top of the page.

<a href="#">link</a>

2.simply "ignores" the link click.

<a href="#" onclick="return false;">link</a>

<a href="#" onclick="foo(); return false;">link</a>

<a href="#" onclick="return foo();">link</a>

<a href="javascript:;">link</a>

<a href="javascript:void(0);">link</a>

<a href="javascript:return false;">link</a>

$('#myDiv a[href]').click(function (event) { 
      event.preventDefault();
      // your other click code here
});

The hash is safest, just in case your user has Javascript disabled.
You can solve it easily using jQuery to all the links with this value in your document :

$('a[href="#"]').click(function(e) {
    e.preventDefault ? e.preventDefault() : e.returnValue = false;
});