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.
-d -o dac ; Required settings for WebAudio: sr = 48000 ksmps = 128 nchnls = 2 nchnls_i = 1 ; ksmps = 64 instr 1 ifftsize = 1024 kcnt init 0 kIn[] init ifftsize kOut[] init ifftsize a1 oscili 0dbfs/2, 440 if kcnt >= ifftsize then kCmplx[] r2c kIn kSpec[] fft kCmplx kCmplx fftinv kSpec kOut c2r kCmplx kcnt = 0 endif kIn[] shiftin a1 a2 shiftout kOut kcnt += ksmps out a2 endin i1 0 10