JavaScript
<!DOCTYPE HTML>
<html lang="ja-JP">
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
</body>
<script type="text/javascript">
str = "";
str += Math.max(1,12,34,21,9) + "<br>";
str += Math.max(42,67,55,33,7,22) + "<br>";
var data1 = 30;
var data2 = 20;
str += Math.max(data1, data2) + "<br>";
document.getElementsByTagName("body")[0].innerHTML = str;
</script>
</html>
PHP
<?php
header("Content-type: text/html; charset=utf-8");
echo max(1,12,34,21,9) . "<br>";
echo max(42,67,55,33,7,22) . "<br>";
$data1 = 30;
$data2 = 20;
echo max($data1, $data2) . "<br>";
?>