document.querySelector(".pink").addEventListener("click", function() {setColor(".pink")},false);
document.querySelector(".blue").addEventListener("click", function() {setColor(".blue")},false);
document.querySelector(".orange").addEventListener("click", function() {setColor(".orange")},false);
document.querySelector(".grey").addEventListener("click", function() {setColor(".grey")},false);

function setColor(color){
  var colorCode = "#000000";
  switch(color){
    case ".pink":
      colorCode = "#E91E63";
      break;
    case ".blue":
      colorCode = "#2196F3";
      break;
    case ".orange":
      colorCode = "#FF9800";
      break;
    case ".grey":
      colorCode = "#9E9E9E";
      break;
  }
  setStickerColor("sticker", colorCode);
  setStickerColor("sticker2", colorCode);
}

function setStickerColor(name, colorCode) {
  document.getElementById(name).style.backgroundColor = colorCode;
};