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('')