用flex弹性布局让盒子居中
<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>
* {
margin: 0;
padding: 0;
}
.box {
margin: 100px auto;
width: 500px;
height: 500px;
background-color: aqua;
/* 开启弹性布局写在 父元素上 */
display: flex;
/* 让盒子按主轴x轴居中 */
justify-content: center;
/* 让盒子按侧轴y轴居中 */
align-items: center;
}
.box1 {
width: 200px;
height: 200px;
background-color: blue;
}
</style>
</head>
<body>
<div class="box">
<div class="box1"></div>
</div>
</body>
</html>
用translate让盒子居中
<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 {
/* 给父盒子添加相对定位 */
position: relative;
width: 500px;
height: 500px;
background-color: aqua;
}
.box1 {
/* 给子盒子添加绝对定位 */
position: absolute;
width: 200px;
height: 200px;
background-color: blue;
/* 整体向右移和下移，父盒子的50%。 */
left: 50%;
top: 50%;
/* 向左和上移动自己宽度的50% */
transform: translate(-50%,-50%);
}
</style>
</head>
<body>
<div class="box">
<div class="box1"></div>
</div>
</body>
</html>
用margin让盒子居中
<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 {
/* 添加相对定位 */
position: relative;
margin: 0 auto;
width: 600px;
height: 600px;
background-color: cadetblue;
}
.box1 {
/* 添加绝对定位 */
position: absolute;
/* 向右移动整体的50%,并且回退自身宽度的50% */
right: 50%;
margin-right: -100px;
top: 50%;
/* 向上移动整体的50%,并且回退自身宽度的50% */
margin-top: -100px;
width: 200px;
height: 200px;
background-color: chartreuse;
}
</style>
</head>
<body>
<div class="box">
<div class="box1"></div>
</div>
</body>
</html>
用margin让盒子居中的第二种方法
<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 {
/* 添加相对定位 */
position: relative;
margin: 0 auto;
width: 600px;
height: 600px;
background-color: cadetblue;
}
.box1 {
/* 添加绝对定位 */
position: absolute;
/* 让盒子在上下左右,都为0 */
top: 0;
bottom: 0;
left: 0;
right: 0;
width: 200px;
height: 200px;
/* 让盒子上下左右居中 */
margin: auto;
background-color: chartreuse;
}
</style>
</head>
<body>
<div class="box">
<div class="box1"></div>
</div>
</body>
</html>
