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> -d -o dac </CsOptions> <CsInstruments> ; Required settings for WebAudio: sr = 48000 ksmps = 128 nchnls = 2 nchnls_i = 1 ; sr = 48000 ; ksmps = 10 ; nchnls = 2 0dbfs = 1 instr 1 idur = p3 iamp = p4 ifrq1 = p5 ifrq2 = p6 indx1 = p7 indx2 = p8 kenv linen iamp, 0.05, idur, 0.2 a1, a2 crossfm ifrq1, ifrq2, indx1, indx2, 1, 1, 1 outs a1*kenv, a2*kenv endin instr 2 kx init 0.0 kdx init 0.1 kdur init p4 kamp init p5 kndx init 0 kmax init p6 kfq1 init 440.0 kfq2 init 557.0 knx1 init 3.5 knx2 init 4.8 event "i", 1, kx, kdur, kamp, kfq1, kfq2, knx1, knx2 kx = kx + kdx knx1 = knx1 - 0.025 knx2 = knx2 - 0.075 kndx = kndx + 1 if (kndx <= kmax) kgoto nextone turnoff nextone: endin </CsInstruments> <CsScore> f 1 0 16384 10 1 0 i 2 0 2 0.67 0.16 150 i 1 15.1 1.5 0.1 440 557 -0.25 -6.45 0.05 1.2 e </CsScore> </CsoundSynthesizer>