Unexpected token else

I'have into a Syntax error in my javascript code. I'm getting a message of 'Unexpected token else' error. I hope someone can help me with this. Here is my code:

function doRed() {
  for (var pixel of img.values()){
    var avg = (pixel.getRed()+pixel.setGreen()+pixel.getBlue())/3;
    if ( avg() < 128) {
    pixel.setRed(2*avg);
    pixel.setGreen(0);
    pixel.setBlue(0);
  }
    }
  else {
    pixel.setRed(255);
    pixel.setGreen(2*avg - 255);
    pixel.setBlue(2*avg - 255);
  }
  var imgcanvas = document.getElementById("can");
  img.drawTo(imgcanvas);
}