代码：
<html>
<head>
<title>显示浏览器信息</title>
<meta charset="UTF-8">
</head>
<body>
<?php
echo $_SERVER["HTTP_USER_AGENT"];
echo "<br>";
echo PHP_OS;
echo "<br>";
echo __DIR__;
echo "<br>";
echo PHP_VERSION;
echo "<br>";
echo __LINE__;
echo "<br>";
echo __FILE__;
?>
</body>
</html>
执行效果：
