I have a form on a html page which one fills in and submits using email.

The form has been opened in a pop up page,

Once the form has been submitted, (emailed) I need to add some javasript to say either "thank you," in the same window and then close it. Or do something else, that the user knows his form has been submitted. The pop up window that says "thank you" can have a close link on it. I do not need to refresh the parent page or refresh anything since the form is an email one.

Any suggestions what to add where? here is the relevant part of the code below. The first part is the code of the pop up window that is used to open it

<a href="page.htm" onClick="NewWindow(this.href,'name','550','430','Yes');return false;">
next is the relevant parts of the email form

<form action="mailto:email@website.com" method="POST" enctype="multipart/form-data" name="pledgeForm">
  <td align="left"><input type="submit" value="Email This Form">
any help appreciated