how to test regex email after complete email entered in javasctior code example

Example 1: email regex javascript

/* JavaScript: validating email address */

isValidEmail("[email protected]"); // true

function isValidEmail(email) {
	var emailRegex = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
	return !!email && typeof email === 'string'
		&& email.match(emailformat)};
};

Example 2: validate email function

# Language: Perl

sub Validate_Email($)
{
   my $sEmail = $_[0];
   my $sRetMsg = "";

   my $sUserNmRegex = "^[[:alnum:]]+([.!#\$\%&'*+-\/=?^_'{|]?[[:alnum:]]+)*";
   my $sDomainRegex = "@[[:alnum:]]+([.-]{1}[[:alnum:]]+)*";
   my $sEndRegex = "([.]{1}[[:alnum:]]+)+";

   #  Work
   #--------#

   if ($sEmail =~ /$sUserNmRegex$sDomainRegex$sEndRegex$/) {
      $sRetMsg = "Email is valid";
   }
   else {
      $sRetMsg = "Email is not valid";
   }

   return $sRetMsg;
}

my $sEmail = '[email protected]';
print "[Email:$sEmail] : " . Validate_Email($sEmail) . "\n";

# OUTPUT -> [Email:[email protected]] : Email is valid