//2011-11-27 星期日 //正则实战（2）： Preg_match验证URL $subscr=$_REQUEST['subscr'];  //url validation if (preg_match('|^http(s)?://[a-z0-9-]+(.[a-z0-9-]+)*(:[0-9]+)?(/.*)?$|i', $subscr))  {  print "$subscr url OK.";  } else {  print "$subscr url not valid!";  }  //echo("$subscr");  ?>  用ereg进行邮箱验证： function validateMail($mail) {  if($mail !== "") {  if(ereg("^[-A-Za-z0-9_]+[-A-Za-z0-9_.]*[@]{1}[-A-Za-z0-9_]+[-A-Za-z0-9_.]*[.]{1}[A-Za-z]{2,5}$", $mail)) {  return true;  } else {  return false;  }  } else {  return false;  }  }  ?>  IP地址匹配验证： function validateIpAddress($ip_addr)  {  //first of all the format of the ip address is matched  if(preg_match("/^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/",$ip_addr))  {  //now all the intger values are separated  $parts=explode(".",$ip_addr);  //now we need to check each part can range from 0-255  foreach($parts as $ip_parts)  {  if(intval($ip_parts)>255 || intval($ip_parts)<0)  return false; //if number is not within range of 0-255  }  return true;  }  else  return false;   }  UK 邮编验证： function IsPostcode($postcode) {  $postcode = strtoupper($postcode);  if(ereg("((GIR 0AA)|(TDCU 1ZZ)|(ASCN 1ZZ)|(BIQQ 1ZZ)|(BBND 1ZZ)"  ."|(FIQQ 1ZZ)|(PCRN 1ZZ)|(STHL 1ZZ)|(SIQQ 1ZZ)|(TKCA 1ZZ)"  ."|[A-PR-UWYZ]([0-9]{1,2}|([A-HK-Y][0-9]"  ."|[A-HK-Y][0-9]([0-9]|[ABEHMNPRV-Y]))"  ."|[0-9][A-HJKS-UW]) [0-9][ABD-HJLNP-UW-Z]{2})", $postcode)) {  return $postcode;  } else {  return FALSE;  }  }  ?>  SSN 和邮编验证： function isValid($type,$var) {  $valid = false;  switch ($type) {  case "IP":  if (ereg('^([0-9]{1,3}\.){3}[0-9]{1,3}$',$var)) {  $valid = true;  }  break;  case “URL”:  if (ereg("^[a-zA-Z0-9\-\.]+\.(com|org|net|mil|edu)$",$var)) {  $valid = true;  }  break;  case “SSN”:  if (ereg("^[0-9]{3}[- ][0-9]{2}[- ][0-9]{4}|[0-9]{9}$",$var)) {  $valid = true;  }  break;  case “CC”:  if (ereg("^([0-9]{4}[- ]){3}[0-9]{4}|[0-9]{16}$",$var)) {  $valid = true;  }  break;  case “ISBN”:  if (ereg("^[0-9]{9}[[0-9]|X|x]$",$var)) {  $valid = true;  }  break;  case “Date”:  if (ereg("^([0-9][0-2]|[0-9])\/([0-2][0-9]|3[01]|[0-9])\/[0-9]{4}|([0-9][0-2]|[0-9])-([0-2][0-9]|3[01]|[0-9])-[0-9]{4}$",$var)) {  $valid = true;  }  break;  case “Zip”:  if (ereg("^[0-9]{5}(-[0-9]{4})?$",$var)) {  $valid = true;  }  break;  case "Phone":  if (ereg("^((\([0-9]{3}\) ?)|([0-9]{3}-))?[0-9]{3}-[0-9]{4}$",$var)) {  $valid = true;  }  break;  case “HexColor”:  if (ereg('^#?([a-f]|[A-F]|[0-9]){3}(([a-f]|[A-F]|[0-9]){3})?$',$var)) {  $valid = true;  }  break;  case “User”:  if (ereg("^[a-zA-Z0-9_]{3,16}$",$var)) {  $valid = true;  }  break;  }  return $valid;  }