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JavaScript JavaScript and the DOM (Retiring) Getting a Handle on the DOM Selecting by Id

Posted by Eason Biggs
Eason Biggs
6,383 Points

TypeError: 'undefined' when defining a variable using getElementByID

When trying to set the button variable equal to the sayPhrase button, it's raising a TypeError: undefined (evaluating 'document.GetElementByID('sayPhrase'); . Just not sure why this isn't working as it works with similar examples in console.

js/app.js 
let button = document.getElementByID('sayPhrase');
let input;

button.addEventListener('click', () => {
  alert(input.value);
});
index.html 
<!DOCTYPE html>
<html>
  <head>
    <title>Phrase Sayer</title>
  </head>
  <body>
    <p><input type="text" id="phraseText"></p>
    <p><button id="sayPhrase">Say Phrase</button></p>
    <script src="js/app.js"></script>
  </body>
</html>

2 Answers

Adam Pengh
Adam Pengh
29,881 Points
Adam Pengh
Adam Pengh
29,881 Points

You just have to be careful on the getElementById capitalization. You have getElementByID with both letters in ID capitalized.

let button = document.getElementById('sayPhrase');
Eason Biggs
Eason Biggs
6,383 Points
Eason Biggs
Eason Biggs
6,383 Points

facepalm Not sure how I missed that one, thanks!