This links will show you various pictures of the new graphics engine that HTML5 allows Runescape to use:
http://imgur.com/a/kUmq2#0
http://i.imgur.com/mMqQGXp.jpg
This one showing a main difference between the java run login and graphics version of Runescape and the HTML5 version.
Look to the right of the screen, where you can see the core usage of the players pc (the player that took the pictures):
Spoiler
A few of the changes that the switch to HTML5 allows and changes that will be introduced after the change:1: Graphical updates - Includes increased draw distance, "real skies", weather effects, dynamic shadows, real time reflects, a new water shader, lighting effects & richer colour palette as mentioned in Runescape Behind The Scenes Video 48. http://www.youtube.com/watch?v=cFlCUQQWx6s
2: High Fidelity Sound
3: A Clothes editing system, allowing players to dress themselves as they wish
4: Customizable Interfaces
Stay on topic or I will smite you.