The good thing is - it will fallback to flash if the native HTML5 wasn't supported. You won't have to do anything to support old browsers at all, it will do it automatically. The images captured will be exported as JPEG or PNG Data URIs which you will able to upload image data to server easily.
WebcamJS has quite a few options, you can set image format, jpeg quality and force using Adobe Flash fallback mode. To help you start using it, they've provided a few demonstrations and tutorials as guide.
Though the native HTML5 isn't widely supported, it will fallback to flash if required. It's a matter of time for other browsers such as IE to support it.
|Mac OS X||Chrome 30+||Works -- Chrome 47+ requires HTTPS|
|Mac OS X||Firefox 20+||Works|
|Mac OS X||Safari 6+||Requires Adobe Flash Player|
|Windows||Chrome 30+||Works -- Chrome 47+ requires HTTPS|
|Windows||IE 9||Requires Adobe Flash Player|
|Windows||IE 10||Requires Adobe Flash Player|
|Windows||IE 11||Requires Adobe Flash Player|