.NET Validation emulate

Example code

<asp:TextBox runat="server" id="textbox" Text="" />
<br />
<asp:RequiredFieldValidator ControlToValidate="textbox" EnableClientScript="True"
     text="Textbox content is empty" runat="server" />
<br />
<osb:SuperButton runat="server" Text="Submit" SkinStyle="amazon" isSubmit="true"
     Validate="return (typeof(Page_ClientValidate) != 'function' || Page_ClientValidate());" />



 
Submit