Javascript-How can I change style of my app in a click and change again in a second click and return to my initial style in third click

I'm making a calculator with Javascript and I want to make a button that if I click on it whole style of my project changes and if I click again whole style changes again and at third click it returns to initial style

I don't have any Idea how I can change whole style for three times just with one button?

Solution

You can create different css classes and put them in an array. Everytime you click on a button you can switch styles by changing index. Since you did not provide any code here is an example.

let styleIndex = 0;
const styles = ['style1', 'style2', 'style3']; // styles array

function changeStyle() {
    styleIndex = (styleIndex + 1) % styles.length;
    document.body.className = styles[styleIndex];
}

body.style1 {
    background-color: white;
    color: black;
}

body.style2 {
    background-color: black;
    color: white;
}

body.style3 {
    background-color: blue;
    color: yellow;
}

/* You can change the css classes depends on your choice and application */

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Calculator</title>
    <link rel="stylesheet" href="styles.css">
</head>
<body class="style1">
    <button onclick="changeStyle()">Click to change background color</button>
    <script src="script.js"></script>
</body>
</html>