Accessing id attribute in a p-vie method

[sqllyw]

Hi,
got a simple app:

 <ul v-on:click="tab_click($event.target)">
                <li class="is-active" id="f"><a>Foo</a></li>
                <li id="b"><a>Bar</a></li>
            </ul>

I like to access the id of element 'li' in the tab_click, however it always empty:

  tab_click(el) {
                console.log(el)
                console.log(el.id)
            }

jsFiddle

What am I missing here? Thanks.

[sqllyw]

should have been in the :

<li class="is-active" ><a id='f'>Foo</a></li>