Display a GUI window. The window need not have any contents, but should respond to requests to be closed.

-- demo\rosetta\Window_creation.exw
with javascript_semantics
include pGUI.e
IupOpen()
IupShow(IupDialog(IupVbox({IupLabel("hello")},"MARGIN=200x200"),"TITLE=Hello"))
if platform()!=JS then
    IupMainLoop()
    IupClose()
end if
