As said earlier, people are using more of smartphones for browsing rather than desktops. And, it is also a fact that a number of tablets and smartphones do not support Flash. Thus, you must minimize the use of JavaScript, Flash and animations on your website to avoid restraining of navigability. Also, those devices that use Flash may be using an outdated version. So, you can instead opt for HTML5 in case of animations, which is a far better substitute for Flash.