1. Flex layout
<!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>盒模型测试</title>
</head>
<style>
.div-parent{
width: 100px;
height: 100px;
border: 1px solid red;
display: flex;
justify-content: center;
align-items: center;
}
.div-child{
width: 40px;
height: 40px;
border: 1px solid blue;
}
</style>
<body>
<p>Flex布局</p>
<div class="div-parent">
<div class="div-child"></div>
</div>
</body>
</html>
2. display attribute
<!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>盒模型测试</title>
</head>
<style>
.div-parent{
width: 100px;
height: 100px;
border: 1px solid red;
display: table-cell;
vertical-align: middle;
}
.div-child{
width: 40px;
height: 40px;
border: 1px solid blue;
margin: 0 auto;
}
</style>
<body>
<p>display属性</p>
<div class="div-parent">
<div class="div-child"></div>
</div>
</body>
</html>
3. css positioning (specific width and height)
<!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>盒模型测试</title>
</head>
<style>
.div-parent{
width: 100px;
height: 100px;
border: 1px solid red;
position: relative;
}
.div-child{
width: 40px;
height: 40px;
border: 1px solid blue;
position: absolute;
top: 50%;
left: 50%;
margin:-20px 0 0 -20px;
}
</style>
<body>
<p>css定位（具体宽高）</p>
<div class="div-parent">
<div class="div-child"></div>
</div>
</body>
</html>
4. css positioning (percent width and height)
<!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>盒模型测试</title>
</head>
<style>
.div-parent{
width: 100px;
height: 100px;
border: 1px solid red;
position: relative;
}
.div-child{
width: 40px;
height: 40px;
border: 1px solid blue;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
}
</style>
<body>
<p>css定位（百分比宽高）</p>
<div class="div-parent">
<div class="div-child"></div>
</div>
</body>
</html>
