Javascript/windows - Open and close window with one click

I'm trying to both open a new window and close a window with one click. I've got it working in I.E., but it doesn't work in NN. The script I'm using is as follows:

function closopen()
{
window.open("contact.htm","","toolbar=0,menubar=0,status=0,width=600,height=500,top=50,left=100");
self.close();
}

Any ideas on what I can do to make this work in NN?

Thanks.