Javascript简单动态修改多个class名

效果

1.html:

11
11
11
11

2.css

.aaa0{
    width: 100px;
    height: 100px;
    background-color: green;
}
.aaa1{
    width: 100px;
    height: 100px;
    background-color: red;
}
.aaa2{
    width: 100px;
    height: 100px;
    background-color: blue;
}

3.js