Hello!
I opened a new window using 'resizable=no'.
Can the child window make itself resizable even if it's opened with
'resizable=no'?
Yes, it can.
'resizable=no' is just a general hint to the window manager not to
provide resize widgets.It's up to the window manager to obey it and up
to the user to override it. Not necessarily with Javascript - there are
easier and faster ways.
I, for example, whenever face a non-resizable popup (it annoys the hell
off me), call the mouse gesture of "duplicate window". The same page
gets opened in a standard, fully-featured browser window, then I just
close the annoying popup. Bookmark the page, then open the bookmark,
window settings won't be remembered. Set window.width, window.height
from a bookmarklet.
The options are countless. And if you wonder why there's so many of
them, non-resizable windows are EXTREMELY annoying, so users developed
all kinds of workarounds. They have them and they will use them against
you. And send you their worst regards.