>使用Drag and Drop Files捕获文件
>在Form Data Object中发布文件
>回复您要播放的音频项目的URL
>使用音频API播放音频

此jsFiddle允许您将音频文件拖动到某个区域,然后它将播放该文件.

您应该能够使用JavaScriptAudioNode的onaudioprocess事件来获取当前幅度.

编辑：

根据JaapH的说法,我再次对此进行了研究.处理器用于获取适当的事件来渲染画布.所以它并不是真的需要.此jsFiddle与下面相同.但是,它使用requestAnimationFrame而不是处理器.

这是旧代码,请参阅上面的使用请求动画框架的小提琴：

var context = new (window.AudioContext || window.webkitAudioContext)();
var source;
var processor;
var analyser;
var xhr;

function initAudio(data) {
    source = context.createBufferSource();

    if(context.decodeAudioData) {
        context.decodeAudioData(data,function(buffer) {
            source.buffer = buffer;
            createAudio();
        },function(e) {
            console.log(e);
        });
    } else {
        source.buffer = context.createBuffer(data,false /*mixToMono*/);
        createAudio();
    }
}

function createAudio() {
    processor = context.createJavaScriptNode(2048 /*bufferSize*/,1 /*num inputs*/,1 /*numoutputs*/);
    processor.onaudioprocess = processAudio;
    analyser = context.createAnalyser();

    source.connect(context.destination);
    source.connect(analyser);

    analyser.connect(processor);
    processor.connect(context.destination);

    source.noteOn(0);
    setTimeout(disconnect,source.buffer.duration * 1000);
}

function disconnect() {
    source.noteOff(0);
    source.disconnect(0);
    processor.disconnect(0);
    analyser.disconnect(0);
}

function processAudio(e) {
    var freqByteData = new Uint8Array(analyser.frequencyBinCount);
    analyser.getByteFrequencyData(freqByteData);
    console.log(freqByteData);
}

function handleResult() {
    if (xhr.readyState == 4 /* complete */) {
        switch(xhr.status) {
            case 200: /* Success */
                initAudio(request.response);
                break;
            default:
                break;
        }
        xhr = null;
    }      
}

function dropEvent(evt) {
    evt.stopPropagation();
    evt.preventDefault();

    var droppedFiles = evt.dataTransfer.files;

    //Ajax the file to the server and respond with the data

    var formData = new FormData();
    for(var i = 0; i < droppedFiles.length; ++i) {
            var file = droppedFiles[i];

            files.append(file.name,file);
    }

    xhr = new XMLHttpRequest();
    xhr.open("POST",'URL');  
    xhr.onreadystatechange = handleResult;
    xhr.send(formData);
}

function dragOver(evt) {
    evt.stopPropagation();
    evt.preventDefault();
    return false;
}

var dropArea = document.getElementById('dropArea');
dropArea.addEventListener('drop',dropEvent,false);
dropArea.addEventListener('dragover',dragOver,false);

我希望这有帮助