IFRAME in acumatica form

I am trying to call an external URL from Acumatica from using iframe.

I have tried this and it did not work

<asp:Content ID="cont2" ContentPlaceHolderID="phF" runat="Server">
<px:PXFormView ID="form" runat="server" DataSourceID="ds" DataMember="Document"
    AllowCollapse="False" Width="100%" Height="100%" TabIndex="100">
    <Template>
        <div>
            <iframe src="Site Url"></iframe>
        </div>
    </Template>
    <AutoSize Container="Window" Enabled="True" MinHeight="200" />
</px:PXFormView>

</asp:Content>

I have tried with in table and it worked for me

<asp:Content ID="cont2" ContentPlaceHolderID="phF" runat="Server">
<px:PXFormView ID="form" runat="server" DataSourceID="ds" DataMember="Document" 
    AllowCollapse="False" Width="100%" Height="100%" TabIndex="100" CaptionVisible="false">
    <Template>
        <table runat="server" style="width: 100%;height=1000px">
            <tr>
                <td style="height=800px;width=100%">
                   
      
            <iframe id="myform" src="My Url" width="100%" height="800px" scrolling="no" ></iframe>
        
                    </td>
                </tr>
            </table>
    </Template>
    <AutoSize Container="Window" Enabled="True" MinHeight="200" />
</px:PXFormView>

</asp:Content>