TinyChan

Audio processing example in JavaScript (how to use without Dollchan):

var{sin,cos,floor,random,PI}=Math,TAU=Math.PI*2,mod=(n,m)=>(n%m+m)%m,
    audioCtx=new(AudioContext||webkitAudioContext)(),
    bufferSize=1024,sampleRate=audioCtx.sampleRate,globalTime=0,δt=1/sampleRate,
    scriptNode,isPlaying=false;
function DSP(t){
    //return sin(TAU*220*t);
    return[sin(TAU*440*t)*sin(t),sin(TAU*440*t)*cos(t)];
}
function toggleAudio(){
    if(!scriptNode){
        scriptNode=audioCtx.createScriptProcessor(bufferSize,0,2); //AudioWorklet is recommended today but requires external files.
        scriptNode.onaudioprocess=e=>{
            let outBuffer=e.outputBuffer,signal,
                outL=outBuffer.getChannelData(0),
                outR=outBuffer.getChannelData(1);
            for(let i=0;i<bufferSize;i++){
                signal=DSP(globalTime);
                if(typeof signal==="number"){
                    outL[i]=outR[i]=signal;
                }else{
                    outL[i]=signal[0];outR[i]=signal[1];
                }
                globalTime+=δt;
            }
        };
        scriptNode.connect(audioCtx.destination);
        audioCtx.resume();isPlaying=true;
    }else if(isPlaying){
        scriptNode.disconnect(audioCtx.destination);isPlaying=false;
    }else{
        scriptNode.connect(audioCtx.destination);audioCtx.resume();isPlaying=true;
    }
}
toggleAudio(); //Play, but call again to pause.