This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

The AudioContext.createJavaScriptNode() method creates a JavaScriptNode which is used for directly manipulating audio data with JavaScript.

Important: This method is obsolete, and has been renamed to AudioContext.createScriptProcessor(). See also ScriptProcessorNode.


var jsNode = audioCtx.createJavaScriptNode(bufferSize, numInputChannels, numOutputChannels);


The buffer size must be in units of sample frames, i.e., one of: 256, 512, 1024, 2048, 4096, 8192, or 16384. It controls the frequency of callbacks asking for a buffer refill. Smaller sizes allow for lower latency and higher for better overall quality.
The number of input channels in the audio stream.
The number of output channels in the audio stream.


The following script illustrates the use of createJavaScriptNode():

var SineWave = function(context) {
  var that = this;
  this.x = 0; // Initial sample number
  this.context = context;
  this.node = context.createJavaScriptNode(1024, 1, 1);
  this.node.onaudioprocess = function(e) { that.process(e) };

SineWave.prototype.process = function(e) {
  var data = e.outputBuffer.getChannelData(0);
  for (var i = 0; i < data.length; ++i) {
    data[i] = Math.sin(this.x++);
} = function() {

SineWave.prototype.pause = function() {

See also