Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript and the DOM (Retiring) Responding to User Interaction Event Delegation

Posted by Jacquelyn Springs
Jacquelyn Springs
9,395 Points

What am i doing wrong

app.js 
let section = document.getElementsByTagName('section')[0];

section.addEventListener('click', (e) => {
  e.target.style.backgroundColor = 'rgb(255, 255, 0)';
});

    if (event.target.tagName == 'INPUT') {
  event.target.style.backgroundColor = 'blue';
    }
    });
index.html 
<!DOCTYPE html>
<html>
    <head>
        <title>JavaScript and the DOM</title>
    </head>
    <link rel="stylesheet" href="style.css" />
    <body>
        <section>
            <h1>Making a Webpage Interactive</h1>
            <p>JavaScript is an exciting language that you can use to power web servers, create desktop programs, and even control robots. But JavaScript got its start in the browser way back in 1995.</p>
            <hr>
            <p>Things to Learn</p>
            <ul>
                <li>Item One: <input type="text"></li>
                <li>Item Two: <input type="text"></li>
                <li>Item Three: <input type="text"></li>
                <li>Item Four: <input type="text"></li>
            </ul>
            <button>Save</button>
        </section>
        <script src="app.js"></script>
    </body>
</html>
Mark Casavantes
Mark Casavantes
2,880 Points
Mark Casavantes
Mark Casavantes
2,880 Points

Hello Jacquelyn,

Want to know a trick or two. Get codepen.io and run you code inside their program. Click on the red circle with the excamation point inside it. It will give you hints to where your errors are. It will give the line number and spaces to locate your errors. Codepen.io is free.

Also you can use https://www.jslint.com/ to check your Javascript. You can use https://validator.w3.org/ to check your HTML. These online websites are free.

One thing I found is you are not matching all your () and {}.

I hope I have been helpful to you.

1 Answer

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

It looks like there's a stray line with "});" on it that is causing a bracing mismatch.

But even more important is that the instructions only asked for the condition to be placed around the existing line that changes the color, not for a new color-changing line to be added.

And finally, the argument should be referenced as "e" and not "event". The global variable "event" might contain the same reference, but it's not good practice to use it instead of the passed argument.

Mark Casavantes
Mark Casavantes
2,880 Points
Mark Casavantes
Mark Casavantes
2,880 Points

Hello Steven,

I always learn from you!

Thank you,

Mark