check if email is valid in javascript code example

Example 1: Email validation using javascript

function checkEmail() {

    var email = document.getElementById('txtEmail');
    var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;

    if (!filter.test(email.value)) {
    alert('Please provide a valid email address');
    email.focus;
    return false;
 }
}

- Call the function on Email textbox

Example 2: email validation in javascript

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>JavaScript form validation - checking email</title>
<link rel='stylesheet' href='form-style.css' type='text/css' />      
</head>
<body onload='document.form1.text1.focus()'>
<div class="mail">
<h2>Input an email and Submit</h2>
<form name="form1" action="#"> 
<ul>
<li><input type='text' name='text1'/></li>
<li> </li>
<li class="submit"><input type="submit" name="submit" value="Submit" onclick="ValidateEmail(document.form1.text1)"/></li>
<li> </li>
</ul>
</form>
</div>
<script src="email-validation.js"></script>
</body>
</html>

Example 3: 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:EmailExample@gmail.com] : Email is valid