html5 audio标签在iPhone 6/6s下要定义proload预加载，点击一次就可以播放，否则会要点两次才能播放。其它设备没有发现这个问题。
<audio id="fmaudio" src="https://images.domain.com/audio/library/2017-11/fm-kaibaola2.mp3?1"
preload="true"></audio>
<script>
function playfm(){
var fmaudio = document.getElementById('fmaudio');
var playbtn = document.getElementById('playbtn');
if(!fmaudio.paused){
fmaudio.pause();
playbtn.src="/Public/App/images/fm/play.png";
}else{
fmaudio.play();
playbtn.src="/Public/App/images/fm/pause.png";
}
}
</script>
