[看你有多色﹣暴走微遊戲](http://game.ioxapp.com/color/)

黒を追いかけろ.js

it = function () {
  ls = box.getElementsByTagName('span');
  map = {};
  push = function (col, i) {
    if (map[col]) map[col].push(i);
    else map[col] = [i];
  };
  for(i=0;i<ls.length;++i) push(ls[i].style.backgroundColor, i);
  for(col in map) {
    if (map[col].length == 1)
      ls[map[col][0]].style.backgroundColor = 'black';
    else
      map[col].forEach(function(i) {
        ls[i].style.backgroundColor = 'white';
      });
  }
};
setInterval(it, 20);