How to find a parent with a known class in jQuery?

问题

I have a <div> that has many other <div>s within it, each at a different nesting level. Rather than give every child <div> an identifier, I rather just give the root <div> the identifier. Here’s an example:

<div class="a" id="a5">
  <div class="b">
    <div class="c">
      <a class="d">
      </a>
    </div>
  </div>
</div>

If I write a function in jQuery to respond to class d and I want to find the ID for its parent, class a, how would I do this?

I cannot simply do $('.a').attr('id');, because there are multiple class as. I could find its parent’s parent’s parent’s ID but that seems of poor design, slow, and not very polymorphic (I would have to write different code for finding the ID for class c).

回答1:

Assuming that this is .d, you can write

$(this).closest('.a');

The closest method returns the innermost parent of your element that matches the selector.

回答2:

Pass a selector to the jQuery parents function:

d.parents('.a').attr('id')

EDIT Hmm, actually Slaks's answer is superior if you only want the closest ancestor that matches your selector.

回答3:

You can use parents() to get all parents with the given selector.

Description: Get the ancestors of each element in the current set of matched elements, optionally filtered by a selector.

But parent() will get just the first parent of the element.

Description: Get the parent of each element in the current set of matched elements, optionally filtered by a selector.

jQuery parent() vs. parents()

And there is .parentsUntil() which I think will be the best.

Description: Get the ancestors of each element in the current set of matched elements, up to but not including the element matched by the selector.

回答4:

Use .parentsUntil()

$(".d").parentsUntil(".a");

来源：https://stackoverflow.com/questions/5333426/how-to-find-a-parent-with-a-known-class-in-jquery

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