This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I think the problem is that you have a race condition between the submit and the onclick. I assume they are a synchronus and if your computer manages to execute the close first the submit won't happen. I'd suggest using a button and in the onclick event submit your form and then do your window.close. That should force them to happen one after teh other.