Javascript image uploading window is not closing.

hi new window is not closing. 
here i did the following code for uploading image.
i have two aspx page. form1.aspx and form2.aspx
i wrote the following javascript function in form1.aspx page:
function checksubmission() { window.open('form2.aspx', null, 'height=380, width=550,status= no, resizable= no, scrollbars=no, toolbar=no,location=no,menubar=no '); return false;
}
} </script>

<asp:ImageButton ID="imgupload" runat="server" OnClientClick="return checksubmission();"/>

Note: can you see while uploading doc or image in second form (ie(form2.aspx).  
as i wrote function window.open(...). it is opening new window in form2.aspx. i can upload image or doc, 

after uploading doc ro img, the window is not get closed. how to close the open window. Thank you.