This example demonstrates how to post back selected color to Server (
MS ASP.NET AJAX).
Example code
Script blocks are the same as in
Post back to server example.
<asp:HiddenField runat="server" id="HiddenValue" value="" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
Click to the box:
<obout:ColorPicker runat="server" OnClientOpen="OnColorOpen" OnClientPicked="OnColorPicked"
TargetId="color" TargetProperty="style.backgroundColor" >
<asp:TextBox readOnly="true" id="color" style="cursor: pointer;" runat="server"/>
</obout:ColorPicker>
<asp:Button runat="server" Text="Submit"/><br/><br/>
<asp:label id="Message" runat="server" Text=" " />
</ContentTemplate>
</asp:UpdatePanel>
Download working example 
.