Transparent Background in Processing JS

transparent_bg.js

//width and height are the dimensions of your processing canvas.
processing.setup = function() {
      processing.size(width, height);
      processing.loadPixels();
      for (var i = 0; i < processing.width*processing.height; i++){
        processing.pixels.setPixel(i,0);
      } 
      processing.updatePixels();
    };