Here's the expression:
^([\w\d\-\.]+)@{1}(([\w\d\-]{1,67})|([\w\d\-]+\.[\w\d\-]{1,67}))\.(([a-zA-Z\d]{2,4})(\.[a-zA-Z\d]{2})?)$Here's the way it can be used in ASP.NET Regular Expression Validator:
<asp:RegularExpressionValidator runat="server" ID="EmailAddress" Display="Dynamic" ControlToValidate="txtFirstName" ErrorMessage="Please enter a valid e-mail address" ValidationExpression="^([\w\d\-\.]+)@{1}(([\w\d\-]{1,67})|([\w\d\-]+\.[\w\d\-]{1,67}))\.(([a-zA-Z\d]{2,4})(\.[a-zA-Z\d]{2})?)$" ValidationGroup="CreateUserForm">*</asp:RegularExpressionValidator>Matches: name@domain.com | name@sub-domain.com.au | name@sub1.sub2.domain | name@organization.co.uk | name@domain.tv | name@domain.four | name@mailbox.com.us
Non-Matches: www.domain.com | name@.com | name@domain..com | name@anything@.com | name@com
