Problem with Button click

Hi All,
On my aspx page I am trying to capture user input and then tried to save them in database and also trying to post them onto another page. Now I am using the following code on the button click event:
ASPX CODE:
<asp:Button runat="server" ID="cmdPress"  Text="Save" 
                                                       ValidationGroup="ValidateId"  Height="26px"  onclick="cmdSave_Click"/>

 
CODE BEHIND:
SaveCustomer();
SaveRequest();
cmdPress.Attributes.Add("onClick", "update(" + ID.Text + ");");

 
Now when I click save button then it the page waits and then I have to click again to close the page automaticallly and move to the next page. Can anyone tell me why I will have to click Save but ...