代码（两种方法）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
*{
margin:0;
padding:0;
}
.box{
width:50px;
height:50px;
background:orange;
position: absolute;
}
/* .box:nth-child(1){
left:0;
top:0;
}
.box:nth-child(2){
left:50px;
top:50px;
}
.box:nth-child(3){
left:100px;
top:100px;
} */
</style>
</head>
<body>
<div id="app"></div>
<script>
var box = document.getElementsByClassName('box');
// box[0].style.cssText ='left:0;top:0';
// box[1].style.cssText ='left:50px;top:50px';
// box[2].style.cssText ='left:100px;top:100px';
// box[3].style.cssText ='left:150px;top:150px';
// box[4].style.cssText ='left:200px;top:200px';
// for(var i=0;i<box.length;i++){
// box[i].style.cssText = 'left:'+50 *i + 'px;top:' + 50 * i + 'px;'
// }
for(var i=0;i<10;i++){// 0123456789
document.body.innerHTML += '<div class="box" style="left:'+50 * i+'px;top:'+50 * i+'px;"></div>'
}
</script>
</body>
</html>
效果：
