Modifies the default behavior of the html A tag so that the default action is prevented when the href attribute is empty.

This change permits the easy creation of action links with the ngClick directive without changing the location or causing page reloads, e.g.: <a href="" ng-click="list.addItem()">Add Item</a>

Directive Info

This directive executes at priority level 0.

Usage

as element:
```
<a>
...
</a>
```