Úkoly

Výchozí stav

<!DOCTYPE html>
<html lang="cs">
<head>
    <meta charset="utf-8" />
    <title>Button</title>
 
    <style>
 
    </style>
 
    <script>
      function zelenePozadi(){
        document.body.style.backgroundColor = 'green'
      }
    </script>
</head>
 
<body>
 <button onclick="zelenePozadi()">Zelené</button>
</body>
</html>