quick theremin

theremin.js

// only webkit, please
var DoFreq = 261;
var SiFreq = 494;
var rangeFreq = DoFreq - SiFreq;
var context = new webkitAudioContext(); 
var sineWave = context.createOscillator(); 
sineWave.connect(context.destination); 
sineWave.noteOn(1);
window.addEventListener('mousemove', function(ev) { 
  var totalSize = window.document.width;
  
  sineWave.frequency.value = (ev.clientY * rangeFreq / totalSize) + DoFreq; 
  sineWave.detune.value = ev.clientX;

})