How to close a pop up window and return control to parent page on successs

Question

I am using this code.This pop up window pops up when I clicks a button on the main page.Now I want the pop up window to be closed if the password is successfully changed and reload the main page,but if the password is not changed then refresh the pop up window again. Here is the code.....

<asp:Textbox id="curnt_paswrd" textmode="Password" runat="server" size="30" />
<asp:Textbox id="new_paswrd" textmode="Password" runat="server" size="30" />