Hi osakawebbie,
Please do not create duplicate topics for the same issue. All three of your topics, including the last one (which was still open) have now been combined into one topic.
Generally, we neither explicitly test for or specifically develop for any browsers or devices. In other words, we don’t support or not support any OS, browser or device etc. Instead, we design with standards-compliancy in mind and to keep things simple, clean and as hack-free as is manageable allowing for a solid, easy-to-use and extensible tool for customers.
The extensible part is key here. The default menu is only a default design element, not something that must be used by everyone, it can be both expanded upon or replaced altogether by something more suitable for every individual.
At this time, we have no plans of including a menu that requires JavaScript.
There are also many thousands of plugins when you need to extend your website with something more advanced than what’s found out-of-the-box.
You might give this plugin a try:
http://wordpress.org/plugins/responsive-menu/
Thank you.