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JavaScript JavaScript and the DOM (Retiring) Getting a Handle on the DOM Practice Selecting Elements

Elizabeth Schultz
Elizabeth Schultz
1,989 Points
Posted by Elizabeth Schultz
Elizabeth Schultz
1,989 Points

How do I access a list of items within a tag (<nav>) and store them properly?

"In the following tasks you'll be required to select various elements on the index.html page.

In the app.js file on line 1, select all links in the nav element and assign them to navigationLinks."

I got stuck on this earlier and re-watched the entire collection of videos about querySelectorAll and querySelector and getElementById and getElementsById. I have tried about 10 different variations and cannot get it. Please help.

js/app.js 
let navigationLinks = document.getElementByTagName('nav');
let galleryLinks;
let footerImages;
index.html 
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Nick Pettit | Designer</title>
    <link rel="stylesheet" href="css/normalize.css">
    <link href='http://fonts.googleapis.com/css?family=Changa+One|Open+Sans:400italic,700italic,400,700,800' rel='stylesheet' type='text/css'>
    <link rel="stylesheet" href="css/main.css">
    <link rel="stylesheet" href="css/responsive.css">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
  </head>
  <body>
    <header>
      <a href="index.html" id="logo">
        <h1>Nick Pettit</h1>
        <h2>Designer</h2>
      </a>
      <nav>
        <ul>
          <li><a href="index.html" class="selected">Portfolio</a></li>
          <li><a href="about.html">About</a></li>
          <li><a href="contact.html">Contact</a></li>
        </ul>
      </nav>
    </header>
    <div id="wrapper">
      <section>
        <ul id="gallery">
          <li>
            <a href="img/numbers-01.jpg">
              <img src="img/numbers-01.jpg" alt="">
              <p>Experimentation with color and texture.</p>
            </a>
          </li>
          <li>
            <a href="img/numbers-02.jpg">
              <img src="img/numbers-02.jpg" alt="">
              <p>Playing with blending modes in Photoshop.</p>
            </a>
          </li>
        </ul>
      </section>
      <footer>
        <a href="http://twitter.com/nickrp"><img src="img/twitter-wrap.png" alt="Twitter Logo" class="social-icon"></a>
        <a href="http://facebook.com/nickpettit"><img src="img/facebook-wrap.png" alt="Facebook Logo" class="social-icon"></a>
        <p>&copy; 2016 Nick Pettit.</p>
      </footer>
    </div>
  <script src="js/app.js"></script>
  </body>
</html>
KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,967 Points

I think it would help to go through the teacher's notes for this video . There is a link there to a course on CSS selectors as well as a link to the MDN page regarding querySelectorAll.

2 Answers

KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,967 Points

You could use the querySelectorAll method as follows:

let navigationLinks = document.querySelectorAll('nav a');

note: There is no such thing as getElementsById since the ID identifies a single unique element per page.

Elizabeth Schultz
Elizabeth Schultz
1,989 Points
Elizabeth Schultz
Elizabeth Schultz
1,989 Points

How did you know to put the 'a' at the end of 'nav'? I have not yet had an HTML or CSS class so these things are not yet clear to me.

Ikuyasu Usui
Ikuyasu Usui
36 Points
Ikuyasu Usui
Ikuyasu Usui
36 Points

"nav a" is a CSS selector meaning that the code selects a DOM for 'a' whose ancestor is 'nav'. For example, 'nav' is a CSS selector for 'nav' html tag. In this problem,

<!-- nav tag begins here -->
<nav>
  <ul>
    <!-- [a]nchor tag is seen here as nested within nav tag, and there are three of them -->
    <li><a href="index.html" class="selected">Portfolio</a></li>
    <li><a href="about.html">About</a></li>
    <li><a href="contact.html">Contact</a></li>
  </ul>
</nav>

On the other hand, 

let navigationLinks = document.getElementByTagName('nav');
// or
let navigationLinks = document.querySelectorAll('nav');

will select the whole DOM within <nav> and </nav>, which includes <ul>, <li> ,<a> and text contents in them.

For another example, 

let navigationLinks = document.querySelectorAll('nav a.selected');

will select the only first anchor tag as a DOM, and

let navigationLinks = document.querySelectorAll('nav .selected');

will also select the only first anchor tag (exactly same tag) as a DOM and

let navigationLinks = document.querySelectorAll('nav li .selected');

will also again select the only first anchor tag (exactly same tag) as a DOM.