每次单击按钮，div的宽、高都增加50px。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>点击按钮改变CSS样式</title>
<style type="text/css">
* {
padding:0px;
margin:0px;
}
.box {
width:300px;
height:300px;
border:1px solid #CBC4F7;
font-size:13px;
margin:100px auto;
}
.divWidth {
width:400px;
}
.divHeight {
height:400px;
}
.divBgColor {
background-color:#DCF3B1;
}
p {
padding:15px 5px;
}
ul li {
list-style:none;
width:140px;
height:32px;
text-align:center;
line-height:32px;
background-color:#C4EA84;
border:1px solid #9BEA75;
margin:0px auto;
margin-bottom:10px;
cursor:pointer;
background-image:-webkit-linear-gradient(top, #C4EA84, #53AC28);
background-image:-moz-linear-gradient(top, #C4EA84, #53AC28);
background-image:-o-linear-gradient(top, #C4EA84, #53AC28);
-webkit-border-radius:4px;
-moz-border-radius:4px;
-o-border-radius:4px;
}
</style>
<script type="text/javascript">
window.onload=function(){
var btn1 = document.getElementById("btn1");
var btn2 = document.getElementById("btn2");
var btn3 = document.getElementById("btn3");
funClick = function(btnID,changeClass){
btnID.onclick = function() {
var boxClass = btnID.parentNode.parentNode.className;
var ifClass = boxClass.indexOf(changeClass);
if(ifClass < 0){
boxClass = boxClass + " " + changeClass;
}else {
boxClass = boxClass.replace(changeClass,"");
}
btnID.parentNode.parentNode.className = boxClass;
}
}
funClick(btn1,"divWidth");
funClick(btn2,"divHeight");
funClick(btn3,"divBgColor");
}
</script>
</head>
<body>
<div class="box">
<p>这里是少许文本</p>
<ul>
<li id="btn1">点我调整宽度</li>
<li id="btn2">点我调整高度</li>
<li id="btn3">点我调整背景颜色</li>
</ul>
</div>
</body>
</html>
</html>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
.box {
width:50px;
height:50px;
background:brown;
position:absolute;
left:50%;
top:50%;
transform:translate(-50%,-50%);
}
</style>
</head>
<body>
<button onclick="add()">按钮</button>
<div class="size"></div>
<div class="box"></div>
<script>
let width=50,height=50
function add() {
let box = document.getElementsByClassName('box')[0]
let size = document.getElementsByClassName('size')[0]
width += box.offsetWidth
height += box.offsetHeight
size.innerHTML = `宽:${width},高:${height}`
Object.assign(box.style,{
width:width + 'px',
height:height + 'px'
})
}
</script>
</body>
</html>