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 -odac -M1 ;;;realtime audio out and midi in ;-iadc ;;;uncomment -iadc if realtime audio input is needed too ; For Non-realtime ouput leave only the line below: ; -o midinoteonpch.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 = 32 ; nchnls = 2 0dbfs = 1 instr 1 midinoteonpch p4, p5 ;gets a MIDI note number value as octave-point-decimal value into p4, and MIDI velocity into p5 print p4 ;display the pitch value when it changes and when key is pressed kvel = kvel/127 ;scale midi velocity to 0-1 ipch = p4 icps = cpspch(ipch) ;convert octave-point-decimal value into Hz kenv madsr 0.5, 0.8, 0.8, 0.5 ;amplitude envelope multiplied by asig pluck kenv*kvel, icps, icps, 2, 1 ;velocity value outs asig, asig endin </CsInstruments> <CsScore> f 0 30 ;runs for 30 seconds f 2 0 4096 10 1 i 1 0 2 8.09 100 ; play these notes from score as well i 1 + 2 9.05 100 e </CsScore> </CsoundSynthesizer>