Email validation

[SBh]

Often in forms we take user email-id. However those email ids may not be a valid email id. Here is a simple way to validate the email-id before proceeding

function VALIDATE_EMAIL ( $email ) {
 global $mxrecords;
 if ( $email == '' ) return (-1);
 list ( $username , $domaintld ) = split ( "@" , $email , 2 ) ; 
 $domaintld = strtolower ( $domaintld ) ;
 if ( !getmxrr ( $domaintld , $mxrecords ) || !preg_match ( "(^[-\w\.]+$)" , $username ) )  return 0;
 return 1;
}

Now, use this function to validate email id. just call VALIDATE_EMAIL ('emailid@domain.com') to check it is valid or invalid. Function will return -1 if no email id is given, 0 if invalid email id, 1 if it is valid.