Targeting $(this) within nested for each loops in jQuery

Question

I'm trying to figure out, when iterating through some list items, how to target each "$(this)" equivalent within nested foreach loops. Here is an example of my problem:

$('li').each(function(){
        // I believe $(this) would target each li item...
    $(this).children("li").each(function(){
        // ... but how can I target each of these li items? Doesn't $(this) target the original loop?
    });
});

You want to target li children's ? – Mohammad Adil May 02 '13 at 19:31 — Mohammad Adil, May 02 '13 at 19:31

score 84 · Accepted Answer · answered May 02 '13 at 19:31

84

$('li').each(function(){
    var $this = $(this);
    $this.children("li").each(function(){
        $this; // parent li
        this; // child li
    });
});

answered May 02 '13 at 19:31

Gabe

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@mmmoustache - np glad i could help – Gabe May 02 '13 at 20:36

score 32 · Answer 2 · answered May 02 '13 at 19:36

32

Don't use this! Use function parameters!

$('li').each(function(i, li){
    $(li).children("li").each(function(ii, li2){
        $(li)...
        $(li2)...
    });
});

This is more in keeping with the native JavaScript iterators.

...though an <li> can't be the direct child of another <li>

answered May 02 '13 at 19:36

1

Why are you using `this`, then? `$(this).cildren('li')` as opposed to `li.children('li')` – Elias Van Ootegem May 02 '13 at 19:37
1

@EliasVanOotegem: 'twas a copy/paste omission. Thanks for the heads-up. – May 02 '13 at 19:38
thanks for this, squint. I never quite got function parameters until your example! – mmmoustache May 02 '13 at 20:01
1

This answer should be part of JQuery/SO lore! I didn't even know about the parameters. – dotnetN00b Oct 21 '14 at 21:42

score 10 · Answer 3 · answered May 02 '13 at 19:35

Look at the basic "prototypes" of jQuery functions (or methods, if you will):

$[jQobject].[func]([callback]);

The callback is the function that will be invoked in the context of the jQ object. The context being this, obviously. Put simply that means that:

$('#foo').click(function(){});
   /\                 /\
   || Is the context  ||
   =====================

The same applies to your case, regardless of the loops being nested or not:

$('ul').each(function()
{
    //this is ul
    var that = this;//you'll often see code like this
    $('li', this).each(function()
    {
        //this is li
        //that is parent ul
    });
});

thanks for the explanation - the documentation is a bit daunting at times but you helped me out! — mmmoustache, May 02 '13 at 20:02

score 3 · Answer 4 · answered May 02 '13 at 19:30

3

but how can I target each of these li items? Doesn't $(this) target the original loop?

Nope.

this comes from the function you're directly in.

answered May 02 '13 at 19:30

SLaks

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score 2 · Answer 5 · answered May 02 '13 at 19:30

Nope, this refers to each of the child <li> items. Try it out.

Most (if not all) DOM-interacting jQuery callbacks set this to to the DOM element that you're working with.

You could also write:

$('li').children("li").each(function(){
    var $this = $(this);
});

Targeting $(this) within nested for each loops in jQuery

5 Answers5

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