PC WEB语音合成，语音播放

var msg = new SpeechSynthesisUtterance();
var voices = window.speechSynthesis.getVoices();
msg.voice = voices[64]; // Note: some voices don't support altering params
msg.voiceURI = 'Google 普通话（中国大陆）';
msg.volume = 1; // 0 to 1
msg.rate = 2; // 0.1 to 10
msg.pitch = 0; //0 to 2
msg.text = '你好，世界！';
msg.lang = 'zh-CN';
speechSynthesis.speak(msg);