How to add a CSS class to an HTML element using JavaScript?

Hello everyone! I just started learning JavaScript and came across this task: I need to dynamically change the style of an element on the page when a button is clicked. I know this can be done by adding a CSS class, but I can't figure out how to implement it correctly. I have a simple HTML markup: ```html Click me ``` And a CSS class I want to add: ```css .highlight { background-color: yellow; font-weight: bold; } ``` I tried writing this code, but it doesn't work: ```javascript let div = document.getElementById('myDiv'); div.class = 'highlight'; // Doesn't work ``` Then I found something about `className` online, tried this: ```javascript div.className ```