terrible code made in 5 minutes

<!DOCTYPE html>

<html>
    <head>
      <meta http-equiv="CONTENT-TYPE" content="text/html; charset=UTF-8">
      <title>MeiCode</title>
      </head>
    <body>
        <h3>305111</h3>
        <p>PUZZLE</p>
    </body>
<script>
    var input = prompt("")
    switch(input) {
    case "yume":
    case "Yume":
    case "YUME":
    document.write("<br>"+"contact me with the word");
    break;
    case "no":
    document.write("<br>"+"actUallY, YEs bUt also no no. U what");
    break;
    case "yes":
    document.write("<br>"+"MaybE? Y not?");
    default:
    document.write("<br>."+"NULL");
}
</script>
</html>