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JavaScript JavaScript and the DOM (Retiring) Making Changes to the DOM Getting and Setting Text with textContent and innerHTML

Posted by cloud712
cloud712
7,616 Points

Why 'p.description'?

const p = document.querySelector('p.description');

Could someone help me understand what the 'p.description' means?

'description' is a class, so the dot notation makes sense. I'm confused why it needs to be preceded by a 'p', though.

cloud712
cloud712
7,616 Points

(code is from the video)

index.html

html
<!DOCTYPE html>
<html>
  <head>
    <title>JavaScript and the DOM</title>
    <link rel="stylesheet" href="css/style.css">
  </head>
  <body>
    <h1 id="myHeading">JavaScript and the DOM</h1>
    <p>Making a web page interactive</p>

    <p class=description>Things that are purple:</p>
    <input type="text" class="description">
    <button class="description">Change List Description</button>
    <ul>
      <li>grapes</li>
      <li>amethyst</li>
      <li>lavender</li>
      <li>plums</li>
    </ul>
    <script src="app.js"></script> 
  </body>
</html>

app.js

const input = document.querySelector('input');
const p = document.querySelector('p.description');
const button button = document.querySelector('button');

button.addEventListener ('click', ()=> {
   p.textContent = input.value + ':';
})

2 Answers

Joseph Yhu
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,637 Points

Because there are also an input and a button elements with class description directly below the p element with class description, and you only want to select the p element with class description for that particular code.

cloud712
cloud712
7,616 Points

Ah got it. So if I wanted to select all elements with the class description, then I'd use this instead? (obv it wouldn't work with the code from the class, but I just want to understand)

document.querySelectorAll('.description')
Joseph Yhu
.a{fill-rule:evenodd;}techdegree seal-36
Joseph Yhu
PHP Development Techdegree Graduate 48,637 Points

Yes.

cloud712
cloud712
7,616 Points
cloud712
cloud712
7,616 Points

Thanks Joseph Yhu !