<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>新建网页</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="description" content="布尔教育 http://www.itbool.com" /> <style> div{ width:300px; height:300px; border-bottom:1px solid black; } .test1{ background: green; } .test2{ width: 300px; height: 300px; background: red; } </style> <script> //封装一个函数,返回运算后的值!获取css样式currentStyle,getComputedStyle function getstyle(obj , attr){ return obj.currentStyle ? obj.currentStyle[attr] : getComputedStyle(obj , null)[attr]; } function t() { var div = document.getElementsByTagName('div')[0]; if(div.className.indexOf('test1') >= 0){ div.className = 'test2'; }else{ div.className = 'test1'; } //alert(getstyle(div , 'width')); //return;//返回 div.style.width = parseInt(getstyle(div , 'width')) + 5 + 'px'; div.style.height = parseInt(getstyle(div , 'height')) + 5 + 'px'; div.style.borderBottomWidth = parseInt(getstyle(div , 'borderBottomWidth')) + 1 + 'px'; } </script> </head> <body> <div onclick="t()";> 点击div,使其背景色红绿交替 宽高增加5px; 下边框增粗1px; </div> </body> </html>

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