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Email Address Validation

 

The Regular Expression

^[-!#$%&'*+/0-9=?A-Z^_a-z{|}~](\.?[-!#$%&'*+/0-9=?A-Z^_a-z{|}~])*@[a-zA-Z](-?[a-zA-Z0-9])*(\.[a-zA-Z](-?[a-zA-Z0-9])*)+$

Java Script

function validateEmail(form)
{
  //Validating the email field
   var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/
   if (! form.Email.value.match(re)) {
       alert("Invalid email address");
       form.Email.focus();
       form.Email.select();
       return (false);
   }
   return(true);
}

C#

public static bool isEmail(string inputEmail)
{
   inputEmail  = NulltoString(inputEmail);
   string strRegex = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
         @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
         @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
   Regex re = new Regex(strRegex);
   if (re.IsMatch(inputEmail))
    return ( true);
   else
    return (false);
} ;

PHP

<?
function Verify_Email_Address($email_address)
{
//Assumes that valid email addresses consist of [email protected]
$at = strpos($email_address, "@");
$dot = strrpos($email_address, ".");

if($at === false ||
$dot === false ||
$dot <= $at + 1 ||
$dot == 0 ||
$dot == strlen($email_address) - 1)
return(false);

$user_name = substr($email_address, 0, $at);
$domain_name = substr($email_address, $at + 1, strlen($email_address));

if(Validate_String($user_name) === false ||
Validate_String($domain_name) === false)
return(false);

return(true);
}
?>

VB Script

<script language="vbscript">
function ValidateEmail(sEmail)
    set myExpression = new RegExp
    myExpression.pattern = "^(\w+\.)*(\w+)@(\w+\.)+([a-zA-Z]{2,4})$"
    If myExpression.test(sEmail.value) = True Then
msgbox "Valid Email"
    Else
msgbox "Invalid Email"
    End If
End Function
</script>

<form name="email">
<input type=text name="txtEmail" maxlength=44 width=40>
<input type=button onclick="ValidateEmail(txtEmail)">
</form>