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

Please review my code

I get it for the most part. we are pulling the warning div into the variable warning. We create the listener and add function. Is the code im running in the call back function wrong. If i wanted to use the css selector of ID would #warning{background-color: red} work as well or since we are working with the DOM better to user the style.element. option.

app.js
var warning = document.getElementById("warning");
var button = document.getElementById('makeItRed');
button.addEventListener('click', (warning) => {
   warning.style.backgroundColor = 'red';

});
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
228,991 Points

By naming the parameter of your event handler "warning", it "shadows" (prevents access to) the global "warning" variable you defined in task 2.

Give the parameter another name ("event" or "e" are both commonly used) and the handler will work as expected.