div height inside a table cell

I have a <div> inside a tablecell. I want the div to be the full height of the cell.
I put height:100% in the style - but it does not work

<asp:TableCell ID="tdCustomerLogin" runat="server" HorizontalAlign="Center" VerticalAlign="Top" style="padding:2px; background-color:#33CC4D; border:solid 1px black;">
      <div style="background-color:White; border:solid 1px black; height:100%;">
         .......... other html code
      </div>
</asp:TableCell>


Thanks

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