如何用PHP实现网页动态跳转

<?
//PHP自带函数
Header("Location: http://www.21php.com");

//利用meta
echo '<meta http-equiv="refresh" content="0; url=http://www.21php.com">';

//利用Javascript语言
echo "<script language='javascript'>";
echo " location='http://www.21php.com';";
echo "</script>";
?>