??      function001.php     
<html>
<head>
<title>7 ?????</title>

<style>
.back1{
background-color: yellow;
}
</style>

</head>

<body>
<h1>7.1 ??????????</h1>

<?php
function test(){ #?test????????????
echo "<h1 class =\"back1\">????</h1>\n";
}

test();#test???????????
test();
test();

?>

</body>
</html>