Javascript

Description

Javascript is the programming language of websites. It enables you to

make HTML elements interactive
alter HTML elements or their styling
load content from servers
...

Example

<!DOCTYPE html>
<html>
  <head>
    <title>Page Title</title>
  </head>
  <body>

    <h1>This is a Heading</h1>
    <p>This is a paragraph.</p>
    <button id="click-me">This is a button</button>

    <script>
      var button = document.getElementById('click-me')
      button.addEventListener('click', function () {
        button.innerHTML = 'You clicked me!'
      })
    </script>
  </body>
</html>

Learn more

Basics: https://www.w3schools.com/html/default.asp
Basics (de): https://www.mediaevent.de/javascript/