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JavaScript Interacting with the DOM Responding to Events Adding an Event Listener

Nathaniel Bennett
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Nathaniel Bennett
Full Stack JavaScript Techdegree Student 4,002 Points
Posted by Nathaniel Bennett
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Nathaniel Bennett
Full Stack JavaScript Techdegree Student 4,002 Points

TypeError: 'undefined' is not a function (evaluating 'document.getELementById("makeItRed")')

receiving type error undefined for .getElementById

app.js 
var warning = document.getElementById("warning");
var button = document.getELementById("makeItRed");
index.html 
<!DOCTYPE html>
<html>
    <head>
        <title>Adding an Event Listener</title>
    </head>
    <link rel="stylesheet" href="style.css" />
    <body>
        <div id="warning">
            Warning: My background should be red!
        </div>
        <button id="makeItRed">Make It Red!</button>
        <script src="app.js"></script>
    </body>
</html>

1 Answer

Steven Parker
Steven Parker
243,173 Points
Steven Parker
Steven Parker
243,173 Points

This code has "getE‍L‍ementById" (with a capital "L") instead of "getElementById".
Since JavaScript is case-sensitive, the system sees this as an undefined function.