问题:

I was reading a lot of questions here about getting value of index.

I know how to get li on click index number. However, I need to get the li value when the link within it is clicked.

<ul>
   <li><a class=link href="#"></a></li>
   <li><a class=link href="#"></a></li>
   <li><a class=link href="#"></a></li>
   <li><a class=link href="#"></a></li>
</ul>


$("li a.link").click(function(e) {
    var i = $(this).index();
       alert(i)
});

It won't work because it takes the index of a.link not ul li. How can I get index of the li when a specific a.link is clicked?

回答1:

You can use jQuery's parent() selector to target the index of the parent element of the clicked anchor link.

In this case, it would be: $(this).parent().index();.

$("li a.link").click(function(e) {
    var i = $(this).parent().index();
    alert(i);
});

If you want to get the physical number (e.g. first returns one, second returns two), you'd just add one to the selector:

$("li a.link").click(function(e) {
    var i = $(this).parent().index() + 1;
    alert(i);
});

回答2:

There are two approaches you can take: count which position the clicked li is, or number them beforehand. The second is much more efficient (constant time on a click):

var li_elems = $('li.link'),
    i = 0,
    len = li_elems.length;

for (; i < len; i++) {
   li_elems[i].attr('index', i);
}

$('ul').on('click', 'li.link', function (e) {
  var index = this.getAttribute('index');
  alert(index);
});