function isUrl($str,$mustfilled=false) 

  {// ^[a-z0-9\._-]+@+[a-z0-9\._-]+\.+[a-z]{2,4}$

    return (checkit::check($str,

                  '#^[h^t^t^p]+'.
	          '://'.
		  '[-!\#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+\.'.
		  '[-!\#$%&\'*+\\./0-9=?A-Z^_`a-z{|}~]+$#',
		  $mustfilled));

  }

$inputerror = false; 
include("checkit.php"); 
  if (!checkit::isAlpha($_POST['nname'],true)) {$inputerror[] = "Name";} 
  if (!checkit::isAlpha($_POST['herkunft'])) {$inputerror[] = "Herkunft";} 
  if (!checkit::isEMail($_POST['email'],true)) {$inputerror[] = "EMail";} 
  if (!checkit::isURL($_POST['hpage'],true)) {$inputerror[] = "Homepage";} 
  if (!checkit::filled($_POST['kommentar'])) {$inputerror[] = "Kommentar";} 
  if ((count($inputerror) == 1) && ($inputerror)) { 
      $error_msg="<font size=\"4\" color=\"#ff0000\">[b]Feld $inputerror[0] kontrollieren!</font></td></tr>"; 
  } else if (count($inputerror) > 1) { 
    $error_msg = "<font size=\"4\" color=\"#ff0000\">Felder: "; 
    $error_msg.= "".implode(", ",$inputerror). " kontrollieren!</font></td></tr>";      
  }

<?php 
// checkit.php 
class checkit { 

  function filled($str) 
  { 
    return (strlen(trim($str)) > 0); 
  } 

  function check($str,$pattern,$mustfilled=false) 
  { 
    if (checkit::filled($str)) 
    { 
      $result = (preg_match($pattern,$str)); 
    } 
    else 
    { 
      $result = (!($mustfilled)); 
    } 
    return $result; 
  } 

  function isAlpha($str,$mustfilled=false) 
  { 
    return (checkit::check($str,"/^[a-zA-ZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÑÒÓÔÕÖØÙÚÛÜÝÞß�*áâãäåæçèéêëì�*îïðñòóôõöøùúûüýþÿ\. ,-]+$/",$mustfilled)); 
  } 

  function isNum($str,$mustfilled=false) 
  { 
    return (checkit::check($str,"/^\d+$/",$mustfilled)); 
  } 

  function isAlphaNum($str,$mustfilled=false) 
  { 
    return (checkit::check($str,"/^[a-zA-Z0-9ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÑÒÓÔÕÖØÙÚÛÜÝÞß�*áâãäåæçèéêëì�*îïðñòóôõöøùúûüýþÿ\. ,-]+$/",$mustfilled)); 
  } 
  function isNoHTML($str,$mustfilled=false) 
  { 
    return (checkit::check($str,"/^[^<>\"]+$/",$mustfilled)); 
  } 

  function isSomeText($str,$mustfilled=false) 
  { 
    return (checkit::check($str,"/[a-zA-Z]+/",$mustfilled)); 
  } 

  function isPhone($str,$mustfilled=false) 
  { 
    return (checkit::check($str,"/^[0-9\+][0-9\(\) -]+$/",$mustfilled)); 
  } 

  function isEmail($str,$mustfilled=false) 
  { 
    return (checkit::check($str, 
                '#^[-!\#$%&\'*+\\./0-9=?A-Z^_`a-z{|}~]+'. 
                '@'. 
                '[-!\#$%&\'*+\\/0-9=?A-Z^_`a-z{|}~]+\.'. 
                '[-!\#$%&\'*+\\./0-9=?A-Z^_`a-z{|}~]+$#', 
      $mustfilled)); 
  } 

  function isURL($str,$mustfilled=false) 
  { 
// http://.+\..+$/i 
// z.B. http://www.test.de oder http://test.de 
    return (checkit::check($str, 
      '#^['*+^_`http://.'{|}~]+'. 
      '[*+\\./\..]+$/i#',$mustfilled)); 
  } 
} 
?>

function isUrl($str,$mustfilled=false) 
    return (checkit::check(
$str, '#^((ht|f)tp(s?))(:((\/\/)(?!\/)))(((w){3}\.)?)(([a-zA-Z0-9\-_]+\.)?)([a-zA-Z0-9\-_]+(\.de|de\.vu|pl|fr|ru|com|edu|gov|int|mil|net|org|biz|info|name|pro|museum|co\.uk)))((\/)?(?!\/))(([a-zA-Z0-9\-_\/]*)?)(([a-zA-Z0-9]\.(jpg|jpeg|gif|png|php((3|4|5)?)([\?A-Za-z0-9\:\/\.\=\&]*)|cgi(([a-z0-9\/\.\?\=\&]*)?)|txt|htm(l?)|pdf))?)+$#', $mustfilled));
}