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

Dhruva Goyal
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Dhruva Goyal
Full Stack JavaScript Techdegree Student 4,138 Points
Posted by Dhruva Goyal
.a{fill-rule:evenodd;}techdegree
Dhruva Goyal
Full Stack JavaScript Techdegree Student 4,138 Points

Event Delegation Code Challenge

Hi Guys i tried to do something like this: let section = document.getElementsByTagName('section')[0];

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

but it's not working.. i searched it on the net and found the solution:

section.addEventListener('click', (e) => { if (e.target.tagName != "INPUT") return; e.target.style.backgroundColor = 'rgb(255, 255, 0)'; });

I don't get how the solution works. why do we have a return and a != in the if?

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

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

2 Answers

Vasili Savitski
Vasili Savitski
5,354 Points
Vasili Savitski
Vasili Savitski
5,354 Points

Hi Dhruva,

tagName returns the name of the tag in upper case. That's the reason why your block of code with 'input' doesn't work, and 'INPUT' in the second version works. Try to use 'INPUT' instead.

Vedang Patel
Vedang Patel
7,114 Points
Vedang Patel
Vedang Patel
7,114 Points

Hey Dhruva I found your mistake you are missing a bracket in the 3rd line after e this is how it would look

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

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

I didn't check everything but this caught my attention first