php中email邮件地址验证大全集合

/**
     * Valid Email
     *
     * @access  public
     * @param   string
     * @return  bool
     */
    function valid_email($str)
    {
        return ( ! preg_match("/^([a-z0-9+_-]+)(.[a-z0-9+_-]+)*@([a-z0-9-]+.)+[a-z]{2,6}$/ix", $str)) ? FALSE : TRUE;
    }

/**
 * 判断email格式是否正确
 * @param $email
 */
function is_email($email) {
    return strlen($email) > 6 && preg_match("/^[w-.]+@[w-.]+(.w+)+$/", $email);
}

/**
 * Verifies that an email is valid.
 *
 * Does not grok i18n domains. Not RFC compliant.
 *
 * @since 0.71
 *
 * @param string $email Email address to verify.
 * @param boolean $deprecated Deprecated.
 * @return string|bool Either false or the valid email address.
 */
function is_email( $email, $deprecated = false ) {
    if ( ! empty( $deprecated ) )
        _deprecated_argument( __FUNCTION__, '3.0' );
 
    // Test for the minimum length the email can be
    if ( strlen( $email ) < 3 ) {
        return apply_filters( 'is_email', false, $email, 'email_too_short' );
    }
 
    // Test for an @ character after the first position
    if ( strpos( $email, '@', 1 ) === false ) {
        return apply_filters( 'is_email', false, $email, 'email_no_at' );
    }
 
    // Split out the local and domain parts
    list( $local, $domain ) = explode( '@', $email, 2 );
 
    // LOCAL PART
    // Test for invalid characters
    if ( !preg_match( '/^[a-zA-Z0-9!#$%&'*+/=?^_`{|}~.-]+$/', $local ) ) {
        return apply_filters( 'is_email', false, $email, 'local_invalid_chars' );
    }
 
    // DOMAIN PART
    // Test for sequences of periods
    if ( preg_match( '/.{2,}/', $domain ) ) {
        return apply_filters( 'is_email', false, $email, 'domain_period_sequence' );
    }
 
    // Test for leading and trailing periods and whitespace
    if ( trim( $domain, " tnrx0B." ) !== $domain ) {
        return apply_filters( 'is_email', false, $email, 'domain_period_limits' );
    }
 
    // Split the domain into subs
    $subs = explode( '.', $domain );
 
    // Assume the domain will have at least two subs
    if ( 2 > count( $subs ) ) {
        return apply_filters( 'is_email', false, $email, 'domain_no_periods' );
    }
 
    // Loop through each sub
    foreach ( $subs as $sub ) {
        // Test for leading and trailing hyphens and whitespace
        if ( trim( $sub, " tnrx0B-" ) !== $sub ) {
            return apply_filters( 'is_email', false, $email, 'sub_hyphen_limits' );
        }
 
        // Test for invalid characters
        if ( !preg_match('/^[a-z0-9-]+$/i', $sub ) ) {
            return apply_filters( 'is_email', false, $email, 'sub_invalid_chars' );
        }
    }
 
    // Congratulations your email made it!
    return apply_filters( 'is_email', $email, $email, null );
}