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 No messages MIDI in -odac -iadc -d -M0 ;;;RT audio I/O with MIDI in ; For Non-realtime ouput leave only the line below: ; -o polyaft.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> ; Required settings for WebAudio: sr = 48000 ksmps = 128 nchnls = 2 nchnls_i = 1 sr = 44100 ksmps = 10 nchnls = 1 massign 1, 1 itmp ftgen 1, 0, 1024, 10, 1 ; sine wave instr 1 kcps cpsmidib 2 ; note frequency inote notnum ; note number kaft polyaft inote, 0, 127 ; aftertouch ; interpolate aftertouch to eliminate clicks ktmp phasor 40 ktmp trigger 1 - ktmp, 0.5, 0 kaft tlineto kaft, 0.025, ktmp ; map to sine curve for crossfade kaft = sin(kaft * 3.14159 / 254) * 22000 asnd oscili kaft, kcps, 1 out asnd endin </CsInstruments> <CsScore> t 0 120 f 0 9 2 -2 0 e </CsScore> </CsoundSynthesizer>