PlayGround

[[https://ipv64.net/status/2wbZmYcF|Externer Link]]

$c_f=4{d_a}^2 ~~~~ [{N/mm^2}]$

$S(f)(t)=a_{0}+sum{n=1}{+infty}{a_{n} cos(n omega t)+b_{n} sin(n omega t)}$

delim{lbrace}{matrix{3}{1}{{3x-5y+z=0} {sqrt{2}x-7y+8z=0} {x-8y+9z=0}}}{ }

$delim{|}{{1/N} sum{n=1}{N}{gamma(u_n)} - 1/{2 pi} int{0}{2 pi}{gamma(t) dt}}{|} <= epsilon/3$

<php>
$popularBrowsers = ["Opera","OPR/", "Edg", "Chrome", "Safari", "Firefox", "MSIE", "Trident"];

$userAgent = $_SERVER['HTTP_USER_AGENT'];
$userBrowser = 'Other less popular browsers';
foreach ($popularBrowsers as $browser) {
    if (strpos($userAgent, $browser) !== false) {
        $userBrowser = $browser;
        break;
    }
}

switch ($userBrowser) {
    case 'OPR/':
        $userBrowser = 'Opera';
        break;
    case 'MSIE':
        $userBrowser = 'Internet Explorer';
        break;

    case 'Trident':
        $userBrowser = 'Internet Explorer';
        break;

    case 'Edg':
        $userBrowser = 'Microsoft Edge';
        break;
}

echo "Your browser: " . $userBrowser;
</php>

<php>
echo 'Name des Benutzers: ' . get_current_user();
</php>

<php>
//Get real ip address
function getClientIp()
{
  $ipaddress = '';
  if (getenv('HTTP_CLIENT_IP'))
    $ipaddress = getenv('HTTP_CLIENT_IP');
  else if (getenv('HTTP_X_FORWARDED_FOR'))
    $ipaddress = getenv('HTTP_X_FORWARDED_FOR');
  else if (getenv('HTTP_X_FORWARDED'))
    $ipaddress = getenv('HTTP_X_FORWARDED');
  else if (getenv('HTTP_FORWARDED_FOR'))
    $ipaddress = getenv('HTTP_FORWARDED_FOR');
  else if (getenv('HTTP_FORWARDED'))
    $ipaddress = getenv('HTTP_FORWARDED');
  else if (getenv('REMOTE_ADDR'))
    $ipaddress = getenv('REMOTE_ADDR');
  else
    $ipaddress = 'UNKNOWN';
  return $ipaddress;
}
//Get IP location information
function findCityByIp($ip)
{
  if ($ip === '127.0.0.1') {
    return "No data";
  } else {
    // $assoc = true formatted as text
    $format_data = file_get_contents('http://ip.ws.126.net/ipquery?ip=' . $ip); 
    /*Conversion encoding format*/
    $data = iconv("gb2312", "utf-8//IGNORE", $format_data); 
    preg_match('/lo="(.*?)", lc="(.*?)"/', $data, $matches);
    $location = $matches[1] . ' ' . $matches[2];
    return $location;
  }
}
//Get website source
function getFromPage()
{
  if ($_SERVER['HTTP_REFERER']) return $_SERVER['HTTP_REFERER'];
  return'No data';
}

$ip = getClientIp();   
echo 'IP: ' . $ip . '</br>';
$city = findCityByIp($ip);   
echo 'City: ' . $city . '</br>';
$from = getFromPage();   
echo 'from: ' . $from . '</br>';

</php>

<php> $ip = $_SERVER['REMOTE_ADDR']; echo "https://api.ipregistry.co/{$ip}?key=tryout"; $details = json_decode(file_get_contents("https://api.ipregistry.co/{$ip}?key=tryout")); echo $details->location; </php> <php> </php>