[Miben]

$email=$_POST['email'];

How to catch the single quote or double quote appear in $_POST['email']
and prompt error msg to user?
This is to prevent user from enter email address such as jo'n@example.com
or jo"n@example.com

Do i need this kind of validation?

[Yeroon]

Yes you need to validate if you want to make sure it uses correct syntax. Try something like this

PHP Code:

if(checkEmail($_POST['email'])

{

   $email=$_POST['email'];

}

else

{

   //do something else like warn user.

}

function checkEmail($email)

{

  

  // checks proper syntax

  if( !preg_match( "/^([a-zA-Z0-9])+([a-zA-Z0-9\._-+])*@([a-zA-Z0-9_-])+([a-zA-Z0-9\._-]+)+$/", $email))

  {

    return false;

  } 

The + is included in the username part of the emailaddress, because that is allowed. It is not allowed in domain or extension.

[ianbrind]

This is the code I use.

It checks if the domain is valid.

PHP Code:

function checkEmail($email) 
{
   if(eregi("^[a-zA-Z0-9_]+@[a-zA-Z0-9\-]+\.[a-zA-Z0-9\-\.]+$]", $email)) 
   {
      return false;
   }

   list($Username, $Domain) = split("@",$email);

   if(getmxrr($Domain, $MXHost)) 
   {
      return true;
   }
   else 
   {
      if(fsockopen($Domain, 25, $errno, $errstr, 30)) 
      {
         return true; 
      }
      else 
      {
         return false; 
      }
   }
}

if(checkEmail($_POST['email']) == false) 
{
    echo "The email address you entered is not valid.";
}
else{
// process data
} 

[Yeroon]

Originally Posted by ianbrind

This is the code I use.

It checks if the domain is valid.

True and good check, but will NOT work on Windows based webservers (IIS) serving PHP.

[Miben]

if( !preg_match( "/^([a-zA-Z0-9])+([a-zA-Z0-9\._-+])*@([a-zA-Z0-9_-])+([a-zA-Z0-9\._-]+)+$/", $email))
{
return false;
}

The above give error on compilation fails..
what wrong with it?

How can i prevent user from entering user@hotmail.com.com
or something else which is not a proper mail hostname?

[Miben]

Thanks...solved

[Yeroon]

Originally Posted by Miben

The above give error on compilation fails..
what wrong with it?

How can i prevent user from entering user@hotmail.com.com
or something else which is not a proper mail hostname?

You can use the dns resolving code to check if the domain is valid (hotmail.com.com istnt). But keep In mind that 2 periods in the suffix of the emailaddress is allowed!!

So info@inter.nl.net is a valid email!!