function startTone(btn) {
  if (!tonePlaying) {
    o.frequency.value = freqMap[btn];
    g.gain.setTargetAtTime(volume, context.currentTime + 0.05, 0.025);
    tonePlaying = true;
  }
}
//will continue playing until stop tone s called
will continue playing until stop tone s called
will continue playing until stop tone s called
function startTone(btn) {
  if (!tonePlaying) {
    o.frequency.value = freqMap[btn];
    g.gain.setTargetAtTime(volume, context.currentTime + 0.05, 0.025);
    tonePlaying = true;
  }
}
function startTone ( btn ) { if ( ! tonePlaying ) { o . frequency . value = freqMap [ btn ] ; g . gain . setTargetAtTime ( volume , context . currentTime + 0.05 , 0.025 ) ; tonePlaying = true ; } }
will continue playing until stop tone s called
will continue playing until stop tone s called