html5 piano,javascript - HTML5 Audio , getting the sound of piano - Stack Overflow

I'm assuming you are fairly new to synthesis. Before trying synthesis algorithms in code, I'd recommend playing with some of the software synthesizers that are available - VST or otherwise. This will give you a handle on the kind of parameters you want to be introducing into your algorithm. http://www.soundonsound.com/sos/allsynthsecrets.htm is an index for a series of really good synthesis tutorials. (Start at the bottom - part 1!)

Once you are ready to start experimenting in code, a great place to start would be to introduce an envelope to change the volume or pitch of the sound over time (changing a parameter over time like this is called 'modulation'). This video may be of interest: http://www.youtube.com/watch?v=A6pp6OMU5r8

Bear in mind that almost all acoustic instruments are difficult to convincingly synthesize algorithmically, and by far the easiest way to get close to a piano is to use samples of real piano notes.