jQuery addClass example

Change class name on click in jQuery

HTML

<div class="board"></div>

CSS

.board {
  width: 240px;
}
.board div {
  display: inline-block;
  text-align: center;
  width: 30px;
  height: 30px;
  line-height: 30px;
}
.cell1 {
  background: lightgray;
}

JavaScript

document.querySelector('.board').innerHTML = new Array(64)
  .fill('')
  .map((_, i)=>`<div class="cell${(i&8)>>3 ^ i&1}">${i}</div>`)
  .join('')