Jquery index can't find element (-1) wrong input (with live function)

问题

I like to get the index of the li element. The li elements are created after the page loaded. Jquery returns a -1 not found error.

The structure html (found in dom, not in page source):

<div id="warp-expand">
  <ul>
   <li><div class="song"><div class="list_b"></div><a>test1</a></div></li>
   <li><div class="song"><div class="list_b"></div><a>test2</a></div></li>
  </ul>
</div>

Jquery to get the li index:

 $("#warp-expand ul li a").live('click',function () {

    var x = $("warp-expand ul li").index(this);
    alert(x); //returns -1  

 });

How the li's are made:

 $("#playlister").click(function () {
    $("#jp_playlist_2 ul li").each(function()
    {
    var s = $(this).text();
    $('#warp-expand ul').append('<li><div class="song"><div class="list_b"></div><a>' +s+ '</a></div></li>');
    });

});

回答1:

Here you go:

$('#warp-expand a').live('click',function () {    
    var idx = $(this).closest('li').index();    
});

Live demo: http://jsfiddle.net/Aphrq/1/

So, as you can see, calling index() without any parameters works just fine. Just select the element (in this case the corresponding LI element) and call index() on it.

---

Also, consider caching your DOM element reference on page-load:

// cache reference on page-load (do this for all your references)
var warp = $('#warp-expand');

// use delegate(), it's better!
warp.delegate('a', 'click', function() {
    var idx = $(this).closest('li').index();        
});

Live demo: http://jsfiddle.net/Aphrq/2/

回答2:

 $("#warp-expand ul li a ").live('click',function () {

    var x = $(this).closest('li').index();
    alert(x); 

 });

http://jsfiddle.net/5vGsE/

来源：https://stackoverflow.com/questions/6540864/jquery-index-cant-find-element-1-wrong-input-with-live-function