preg_match

<?php
function control_url($in) {
  $start   = "(http(s)?:\/\/)";                                             // http://
  $url     = "([\w_-]+)(\.[\w_-]+)*";                                        // www.bla.com
  $user    = "(\/\~[\w_-]+)?";                                               // userdir
  $eind    = "(\/[^\040\t\r\n\.\?]+(\.[^\040\t\r\n\.\?]+)*)*(\/)?";          // files en folders
  $qstring = "(\?[\w_-]+\=([^\#\040\t\r\n]+)(\&[\w_-]=[^\#\040\t\r\n]+)*)?"; // querystring
  $bkmrk   = "(#[\w_-]+)?";                                                  // bookmark

  $exp = "/^".$start.$url.$user.$eind.$qstring.$bkmrk."$/i";
  return preg_match($exp, $in);
}
?>

<?php
function control_url($in) {
  $start   = "(http(s)?:\/\/)";                                             // http://
  $url     = "([\w_-]+)(\.[\w_-]+)*";                                        // www.bla.com
  $user    = "(\/\~[\w_-]+)?";                                               // userdir
  $eind    = "(\/[^\040\t\r\n\.\?]+(\.[^\040\t\r\n\.\?]+)*)*(\/)?";          // files en folders
  $qstring = "(\?[\w_-]+\=([^\#\040\t\r\n]+)(\&[\w_-]=[^\#\040\t\r\n]+)*)?"; // querystring
  $bkmrk   = "(#[\w_-]+)?";                                                  // bookmark
 
  $exp = "/^".$start.$url.$user.$eind.$qstring.$bkmrk."$/i";
  return preg_match($exp, $in);
}
?>