原文地址：https://www.cnblogs.com/xiangru0921/p/6514225.html
<body>
<div id="div">这是一个盒子</div>
<script type="text/javascript">
var div = document.getElementById("div");
//第一种:用cssText
div.style.cssText='600px;height:250px;border:1px red solid;text-align: center;line-height: 250px;';
//第二种：用setProperty()
div.style.setProperty('width','700px');
div.style.setProperty('height','300px');
div.style.setProperty('line-height','300px');
div.style.setProperty('background','#f00');
div.style.setProperty('color','#fff');
div.style.setProperty('border','1px solid blue');
div.style.setProperty('text-align','center');
//第三种：使用css属性对应的style属性
div.style.width = "800px";
div.style.height = "250px";
div.style.lineHeight = "250px";
div.style.background = "#000";
div.style.color = "#fff";
div.style.border = "1px solid #111";
div.style.textAlign = "center";
</script>
</body>