for_loop.html

<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>For Loop</title>
  </head>
  <body>
    <script lang="javascript" type="text/javascript">
      for (var i = 1; i < 20; i += 4) {
        document.write(i, "&nbsp;&nbsp;");
      }
      for (var j = 1; j < 20; j++) {
        if (j % 3 == 0) {
          document.write(j, "&nbsp;&nbsp;<br>");
        }
      }
      var sum = 0;
      var fact=1;
      for (var k = 1; k <= 4; k++) {
        sum += k;
      }
      document.write("Sum is ", sum);
    </script>
  </body>
</html>