date format validation

<asp:TextBox ID="Textdob"

runat="server"

placeholder="dd/MM/yyyy">

</asp:TextBox>



<asp:RegularExpressionValidator

Font-Bold="true"

ForeColor="Red"

ID="RegularExpressionValidator1"

runat="server"

ControlToValidate="Textdob"

ErrorMessage="Accept only dd/mm/yyyy format"

ValidationExpression="^(([0-9])|([0-2][0-9])|([3][0-1]))\/(01|02|03|04|05|06|07|08|09|10|11|12)\/\d{4}$">

</asp:RegularExpressionValidator>