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

Posted by ramy rahmiel
ramy rahmiel
11,797 Points

'undefined' is not a function

i am trying to change the color of the ul items but get " 'undefined' is not a function ". what should i do?

js/app.js 
var listItems = document.getElementbyid('rainbow');
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>

3 Answers

Lachlan Stevens
Lachlan Stevens
10,779 Points
Lachlan Stevens
Lachlan Stevens
10,779 Points

Your issue here is that you are trying to access an index of through your variable listItems, but listItems is an object, not an array.

Obviously you're wanting to loop through the li elements under the ul, so you could accomplish this by assigning listItems as document.getElementById('rainbow').children.

Zimri Leijen
Zimri Leijen
11,835 Points
Zimri Leijen
Zimri Leijen
11,835 Points

capitalization matters. document.getElementbyid is not recognized, and therefore will be undefined.

it should be document.getElementById

ramy rahmiel
ramy rahmiel
11,797 Points
ramy rahmiel
ramy rahmiel
11,797 Points

thank you i tried but it still not working. i get: Bummer: There was an error with your code: TypeError: 'undefined' is not an object (evaluating 'listItems[i].style')