javascript实现蜂鸣器beep效果

a=new AudioContext() // browsers limit the number of concurrent audio contexts, so you better re-use'em

function beep(vol, freq, duration){
  v=a.createOscillator()
  u=a.createGain()
  v.connect(u)
  v.frequency.value=freq
  v.type="square"
  u.connect(a.destination)
  u.gain.value=vol*0.01
  v.start(a.currentTime)
  v.stop(a.currentTime+duration*0.001)
}

调用： beep(100, 520, 200)高频beep beep(999, 220, 300)低频boop beep(999, 210, 800); beep(999, 500, 800);长报警Cool noise 原文