共用代码：
<div id="div">这是一个盒子</div>
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";
<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>