php禁止用下载工具来下载文件

        if(strpos($_SERVER["HTTP_USER_AGENT"],"MSIE 8.0"))
    echo "Internet Explorer 8.0"; // 这里可以写其他的执行命令
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"MSIE 7.0"))
    echo "Internet Explorer 7.0";
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"MSIE 6.0"))
    echo "Internet Explorer 6.0";
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"Firefox/3"))
    echo "Firefox 3";
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"Firefox/2"))
    echo "Firefox 2";
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"Chrome"))
    echo "Google Chrome";
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"Safari"))
    echo "Safari";
    else if(strpos($_SERVER["HTTP_USER_AGENT"],"Opera"))
    echo "Opera";
    else echo $_SERVER["HTTP_USER_AGENT"];
    ?>

        if(strpos($_SERVER["HTTP_USER_AGENT"],"MSIE"))echo"禁止用IE浏览器或其他下载工具下载";
    else header("Content-Disposition: attachment; filename='jquery.js'");//写上文件名
    ?>

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