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

Antonella A
Antonella A
2,472 Points
Posted by Antonella A
Antonella A
2,472 Points

using document.getElementsByTagName('ul') I get this error TypeError: 'undefined' is not an object

I have tried a few different ways to solve this problem and they have all returned the same error. Here I am adding the different lines of code Ive tried:

[...] document.querySelectorAll('ul'); [...] document.querySelectorAll('#rainbow');

js/app.js 
const listItems = document.getElementsByTagName('ul');
var colors = ["#C2272D", "#F8931F", "#FFFF01", "#009245", "#0193D9", "#0C04ED", "#612F90"];

for(var i = 0; i < colors.length; i++) {
  listItems[i].style.color = colors[i];    
}
index.html 
<!DOCTYPE html>
<html>
  <head>
    <title>Rainbow!</title>
  </head>
  <body>
    <ul id="rainbow">
      <li>This should be red</li>
      <li>This should be orange</li>
      <li>This should be yellow</li>
      <li>This should be green</li>
      <li>This should be blue</li>
      <li>This should be indigo</li>
      <li>This should be violet</li>
    </ul>
    <script src="js/app.js"></script>
  </body>
</html>

2 Answers

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

The "ul" is the list itself, the individual list items are "li". They are also all children of the list so that's another way:

const listItems = document.querySelectorAll('#rainbow li');     // the conventional way
const listItems = document.getElementById('rainbow').children;  // but this works too
Antonella A
Antonella A
2,472 Points
Antonella A
Antonella A
2,472 Points

Ooh that makes sense. Thank you very much Steven!