Play Note in Web Browser

playnote.js

// playNote(440, 10) will play a 440 Hz sine wave for 10 seconds
//
// Don't forget that the browser requires some user interaction before
// calling the function, otherwise it will block audio output.
//
// Clicking on the web page once should be enough, though.
//
function playNote(freq, duration = 1) {
  const context = new AudioContext();
  const oscillator = context.createOscillator();
  oscillator.type = "sine";
  oscillator.frequency.value = freq;
  oscillator.connect(context.destination);
  oscillator.start();
  oscillator.stop(context.currentTime + duration);
}