Maximum and Mininum Length

<i386:TextBoxLengthValidator id="TextBoxLengthValidator1" MaximumLength="8" ControlToValidate="TextBox1" ErrorMessage="*Entry is too long." runat="server"/>

(8 max. chars)
 

<i386:TextBoxLengthValidator id="Textboxlengthvalidator2" MaximumLength="5" MinimumLength="3" ControlToValidate="TextBox2" ErrorMessage="*Entry is too short or too long." runat="server"/>

(3 - 5 chars)