Javascript Ball Game

Simple Ball game use HTML canvas tag. 

<canvas> is based on the WHATWG canvas specification (known as HTML 5), which is a new HTML tag can be used to draw graphics using scripting, and here I write the javascript-based ball game. Since Microsoft IE doesn't support <canvas> tag now, so only an alternative warning text will display below instead of the ball game. But as I googled, there's really a cool guy implement IE <canvas> tag with VML (Vector Markup Language), here is his blog link

The ball game, actually as a ball simulator, contains a ball and a room. The room is composed of four wall and initial gravity. Users are allowed to add another two element to the simulator, one is a virtual hand, while another is wind, as an alter power simulate to gravity.

The game begin as a ball with initial velocity and basic gravity (as it's initial acceleration). With the right control panel, users could start the game, pause the game( maybe considered as stop game ), reset the game, and make the wind power, which may be considered as an alter power, controllable. The observation panel blow the control buttons collects the statistics of the ball, including velocity, wind ( generally as force/acceleration), position, while all the parameters was divided into x-axis and y-axis part.

( Shortcuts of wind controlling:  Ctrl-left, Ctrl-right, Ctrl-up, Ctrl-down )

Another interesting interactive feature the game provided is that the ball with hand controlling. With Opera, when user move the mouse into the simulator area, the mouse should change to a hand, while it's still pointer in Firefox (it doesn't matter). Just catch the ball (press down left mouse key at the ball), move the ball ( move mouse without release the key ), and throw/drop the ball ( release the ball while moving, bring the ball velocity, which seems like throw out the ball).