<!DOCTYPE html>
<html> <head> <meta charset="UTF-8"> <title></title> <style> div{width:100px;height:100px;border:1px solid #333;} </style> </head> <body> <div id="div1" >123</div> <input id="btn1" type="button" value="按钮" /> <script> var oDiv=document.getElementById('div1'); var oBtn=document.getElementById('btn1'); oDiv.οnclick=function(){ // oDiv.style.width='200px'; oDiv.style.cssText='width: 200px;height:200px;'; } oBtn.οnclick=function(){ oDiv.style.cssText="width: 100px;"; } </script> </body></html>