SOURCE

let wave = w =>[...w].map((a, i) => w.slice(0, i) + a.toUpperCase() + w.slice(i + 1)).filter(a => a != w)
// 生成含100个字母的字符串
let input = '';
for (var i=0; i<100; i++) {
  input += String.fromCharCode(97+Math.ceil(Math.random() * 25));
  i%9 == 0 ? input += ' ' : input += '';
}
let output = wave(input);
// Mexican Wave
for (let i=0; i<output.length; i++) {
  (function(i){
    setTimeout(function(){
      document.getElementById('div').innerHTML = output[i];
    }, 30 * i);    
  })(i);
}

<div id="div"></div>

div {
  width: 400px;
  font-size: 30px;
  letter-spacing: 2px;
  white-space: normal;
}