How can I loop through the function random amount of times?

I'm trying to create a random amount of squares on canvas each time I press the button and then I want them to move up. Right now it completely ignores the for loop and only generates one square instead of random amount. How to solve this?

// Spawn
var numberArray = [0, 60, 120, 180, 240, 300, 360, 420];
var posX = numberArray[Math.floor(Math.random() * numberArray.length)];
var posY = 240;

  function spawnRandomObject() {
    // Game Object
      ctx.fillStyle = '#f2a365';
      ctx.globalCompositeOperation = "destination-over";
      ctx.beginPath();
      ctx.fillRect(posX, posY, 60, 60);
      ctx.stroke();
  }


// Blocks moving up
document.getElementById("button").addEventListener("click", function(){
  // Spawn random amount of objects
  for (var i=0; i<Math.floor((Math.random()*8)+1); i++){
     spawnRandomObject(i);
  }
  posY -=60;
});