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JavaScript JavaScript and the DOM (Retiring) Traversing the DOM Sibling Traversal

what does the (e) in function(e) means? What does the event in function mean? do we use the (e) letter every time?


var list = document.getElementsByTagName('ul')[0];

list.addEventListener('click', function(e) {
  if (e.target.tagName == 'BUTTON') {
    e.target.previousElementSibling.className = 'highlight';
<!DOCTYPE html>
        <title>JavaScript and the DOM</title>
    <link rel="stylesheet" href="style.css" />
            <h1>Making a Webpage Interactive</h1>
            <p>Things to Learn</p>
                <li><p>Element Selection</p><button>Highlight</button></li>
                <li><p>Event Listening</p><button>Highlight</button></li>
                <li><p>DOM Traversal</p><button>Highlight</button></li>
        <script src="app.js"></script>

3 Answers

Hi Hanwen!

The 'e' is a browser window event object that you can add event listeners to harness and corresponding code to handle/respond to (such as clicking on an element).

More info:




I hope that helps.

Stay safe and happy coding!

Thank you Peter

The 'e' means event in function, but I could be wrong.

What does the event in function means? do we use the (e) letter everytime?

By the way, you can actually use any variable name to reference the event object, but traditionally and logically most often 'event' or 'e' (short/abbreviation for 'event') is used.

More info:


I hope that helps.

Stay safe and happy coding!

Thanks for the information!!!