Selecting a child node (DOM)

Question

How can I select the 2nd <a> tag using pure Javascript?

<div class="navigation">
    <a href="/page/2/">Prev</a>
    <a href="/page/4/">Next</a>
</div>

There are multiple possibilities: `document.querySelectorAll('.navigation a')[1]`, `document.querySelector('.navigation').children[1]`, `document.querySelectorAll('.navigation a:nth-child(2)')`, `document.getElementsByClassName('navigation')[0].children[1]`. Depends on your use case. — Sebastian Simon, Sep 29 '15 at 18:39

score 5 · Accepted Answer · edited Sep 29 '15 at 20:37

5

Use the DOM selector getElementsByClassName().

Return Value: an array of elements containing the class name.

Replace the [?] with the index of the target from the return value of the the getElementsByClassName selector. For example, if the the <div> tag containing the <a> tags was the first element of the document with the class name navigation then it would be at index 0 (since it's 0 based) of the return array, therefore you should use [0] for the corresponding element.

Use the .children property to return an HTMLCollection of the child nodes (in this case <a> tags) of which their parent node (in this case the <div> tag).

//JS

document.getElementsByClassName('navigation')[1].children[1];

//HTML

<div class="navigation">
    <a href="/page/1/">Prev</a>
    <a href="/page/2/">Next</a> 
</div>
<div class="navigation">
    <a href="/page/3/">Prev</a>
    <a href="/page/4/">Next</a> (selected element)
</div>
<div class="navigation">
    <a href="/page/5/">Prev</a>
    <a href="/page/6/">Next</a> 
</div>
<div class="navigation">
    <a href="/page/7/">Prev</a>
    <a href="/page/8/">Next</a> 
</div>

edited Sep 29 '15 at 20:37

Jordan Davis

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answered Sep 29 '15 at 18:34

AmmarCSE

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1

Can the downvoter explain why they downvoted? Or is this punishment for answering this question? – AmmarCSE Sep 29 '15 at 18:50
Using `getElementsByTagName` isn't specific at all, your selecting all the `` tags in the whole document... as well as the drop in performance with using a selector such as this one. – Jordan Davis Sep 29 '15 at 18:53
2

@JordanDavis, very good point. Thanks for pointing that out. Thanks for not being an anonymous downvoter. – AmmarCSE Sep 29 '15 at 18:56
Change it to `.getElementsByClassName('navigation')[?].children[1]` as @Xufox mentioned in the main thread, this would be the fastest way depending on how may elements are associated with the `navigation` class... However I would recommend him using an `id` and direct selecting using `getElementById` but we don't have his full source so thats all we can say. – Jordan Davis Sep 29 '15 at 19:00
@JordanDavis, heh, thanks, and thanks again for the tip :) – AmmarCSE Sep 29 '15 at 19:06

Selecting a child node (DOM)

1 Answers1