怎么检查页面URL中是否有某个字符串

  function curPageURL()
{
    $pageURL = 'http';

    if ($_SERVER["HTTPS"] == "on")
    {
        $pageURL .= "s";
    }
    $pageURL .= "://";

    if ($_SERVER["SERVER_PORT"] != "80")
    {
        $pageURL .= $_SERVER["SERVER_NAME"] . ":" . $_SERVER["SERVER_PORT"] . $_SERVER["REQUEST_URI"];
    }
    else
    {
        $pageURL .= $_SERVER["SERVER_NAME"] . $_SERVER["REQUEST_URI"];
    }
    return $pageURL;
}