<td>
    <asp:TextBox runat="server" TextMode="Password" 
Width="100" 
ID="NewPassword2"></asp:TextBox>
</td>
<td>
    <asp:RequiredFieldValidator 
ErrorMessage="*" 
runat="server" 
display="Dynamic" 
ControlToValidate="NewPassword2" 
id="RequiredFieldValidator3">
</asp:RequiredFieldValidator>
    <asp:CompareValidator ControlToValidate="NewPassword2" 
runat="server" Display="Dynamic" 
ControlToCompare="NewPassword" 
ErrorMessage="Please enter and re-enter 
the same new password" 
id="CompareValidator1">
</asp:CompareValidator>
</td>

Example 1: Password validation using server-side controls.