How to make MultiHandleSliderExtender transparent?

I ha开发者_如何学Gove a MultiHandleSliderExtender control on a page with a background image. The control is rendered with a solid white background. How can I make it transparent?

Here's the code:

<table>
  <tr>
    <td>
    <asp:TextBox ID="probabilityFilterStartTextBox" runat="server" Width="30" Text="0"></asp:TextBox>
    </td>
    <td width="200" valign="top">
    <asp:TextBox ID="probabilityTextBox" runat="server" Style="display:none;"></asp:TextBox>
    <asp:MultiHandleSliderExtender ID="probabilityTextBox_MultiHandleSliderExtender" 
        runat="server" Enabled="True" 
        HandleAnimationDuration="0.1" Maximum="100" Minimum="0" 
        Length="200" TargetControlID="probabilityTextBox" Steps="21">
      <MultiHandleSliderTargets>
        <asp:MultiHandleSliderTarget ControlID="probabilityFilterStartTextBox" />
        <asp:MultiHandleSliderTarget ControlID="probabilityFilterEndTextBox" />
      </MultiHandleSliderTargets>
    </asp:MultiHandleSliderExtender>
    </td>
    <td>
    <asp:TextBox ID="probabilityFilterEndTextBox" runat="server" Width="30" Text="100"></asp:TextBox>
    </td>
  </tr>
</table>

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MultiHandleSliderExtender enable to handle multi slider in .Net web application. MultiHandleSlider Properties:

· Minimum - Minimum value allowed.

· Maximum - Maximum value allowed.

· Length - The length of the graphical slider, in pixels.

· Decimals - Number of decimal digits for the value.

· Steps - Number of discrete values inside the slider's range.

· EnableRailClick - Whether clicking on the rail will move the closest handle to the click location.

· EnableKeyboard - Whether slider values can be changed using the keyboard.

· EnableMouseWheel - Whether slider values can be changed using the mouse wheel.

· Increment - For sliders using keyboard or mouse wheel support; determines the number of points to increment or decrement the slider values.

· BoundControlID - For backwards compatibility, allows using classic Slider properties for a single handle.

· RaiseChangeOnlyOnMouseUp - If true, fires the change event on the extended TextBox only when the left mouse button is released.

· MultiHandleSliderTargets - An inner property describing each handle on the slider.

· ControlID - The TextBox or Label whose value is bound to this handle.

For more information you may check out the following link... http://mindstick.com/Articles/c214c6a1-e2eb-489d-9730-3d854c39aba0/?Ajax%20Toolkit%20MultiHandleSliderExtender%20Control%20in%20ASP.Net

Thanks !!!!