How to hide textfields on in a webform

I am trying to hide multiple textfields i have nested inside a div element. Here is an example of the div element and the script:
 
<div id="addfriend1"> <p>*First Name:<asp:TextBox ID="txtRefFirstNm13" runat="server" Width="135px"></asp:TextBox> *Last Name:<asp:TextBox ID="txtRefLastNm13" runat="server" Width="135px"></asp:TextBox> *Email Address:<asp:TextBox ID="txtRefEmail13" runat="server" Width="140px"></asp:TextBox> <asp:RegularExpressionValidator ID="RegularExpressionValidator14" runat="server" ControlToValidate="txtRefEmail13" ErrorMessage="**invalid email address" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionVa ...