大话Web-Audio-Api

<script>

    var context;

    var musicBuffer;

    window.addEventListener('load',init,false);

    function init()

    {

        try{

            window.AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext || window.msAudioContext;

            context = new window.AudioContext();

            loadSound("m.mp3");//获取音频

        }

        catch (e) {

            alert(e);

        }

    }

    //获取音频数据

    function loadSound(url){

        var request = new XMLHttpRequest();

        request.open('GET',url,true);

        request.responseType= 'arraybuffer';

        request.send();

        //下面就是对音频文件的异步解析

        request.onload = function(){

            context.decodeAudioData(request.response,function(buffer){

                musicBuffer = buffer;

                console.log(context);

                console.log(musicBuffer);

                playSound(context, musicBuffer);//获取成功后播放

            });

        }

    }

    //播放音频数据

    function playSound(audioContext, buffer) {

        var audioBufferSouceNode = audioContext.createBufferSource(),

            analyser = audioContext.createAnalyser();

        //将source与分析器连接

        audioBufferSouceNode.connect(analyser);

        //将分析器与destination连接，这样才能形成到达扬声器的通路

        analyser.connect(audioContext.destination);

        //将上一步解码得到的buffer数据赋值给source

        audioBufferSouceNode.buffer = buffer;

        //播放

        audioBufferSouceNode.start(0);

        //音乐响起后，把analyser传递到另一个方法开始绘制频谱图了，因为绘图需要的信息要从analyser里面获取

        //this._drawSpectrum(analyser);//可以绘制波形图

    }

</script>