This should play if your Web browser has WebAssembly enabled (most do). Most examples will play unless they need to load files. The first time you click Play, Csound will spend a few seconds loading, then play. You can edit this code and replay it.
<CsoundSynthesizer> <CsOptions> ; Select audio/midi flags here according to platform ; Audio out Audio in -odac ;;;RT audio out ; For Non-realtime ouput leave only the line below: ;-o lpf18.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> ; Required settings for WebAudio: sr = 48000 ksmps = 128 nchnls = 2 nchnls_i = 1 ; by Sean Costello ; sr = 44100 ; ksmps = 32 ; nchnls = 2 0dbfs = 1 instr 1 idur = p3 ifreq = p4 iamp = p5 iharms = (sr*.4) / ifreq asig gbuzz .3, ifreq, iharms, 1, .9, 1 ; Sawtooth-like waveform kfreq linseg 1, idur * 0.5, 5000, idur * 0.5, 1 ; Envelope to control filter cutoff afilt lowpass2 asig,kfreq, 30 kenv linseg 0, .1, iamp, idur -.2, iamp, .1, 0 ; Simple amplitude envelope outs afilt * kenv, afilt * kenv endin </CsInstruments> <CsScore> f1 0 8192 9 1 1 .25 ; frq amp i1 0 5 100 .15 i1 5 5 200 .12 e </CsScore> </CsoundSynthesizer>