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内外边距定位与浮动-0705
XXXX.的博客
Original
628 people have browsed it

1.内边距:增加padding盒子会被撑开。解决的三种办法:(1)增加padding之后重新设置盒子宽高,是宽高加padding等于原先的宽高。(2)宽度分离;给盒子增加一个***。嵌套盒子只会继承他宽度,然后设置padding(3)box-sizing 利用box-sizing将父级盒子的宽度作用于边框上而不是内容上,将宽度作用于边框上之后,padding就不会被撑开。

实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx2.css">
    <title>内边距padding</title>
</head>
<body>
<div class="box1">
    <img src="static/images/girl.jpg" alt="小女孩" width="200px">
</div>
<hr>
<div class="wrap">
    <div class="box2">
        <img src="static/images/girl.jpg" alt="小女孩" width="200px">
    </div>
</div>

<!--<hr> 子盒作用父盒子的内容-->
<hr>
<div class="box3">
    <img src="static/images/girl.jpg" alt="小女孩" width="200px">
</div>
</div>
</body>
</html>

.box1 {
    width: 300px;
    height: 300px;
    background-color: yellowgreen;
    border: 1px solid black;
    padding-left: 50px;
}
.box1 {
    padding: 50px;
}

.box1 {
    width: 200px;
    height: 200px;
}


/*嵌套盒子之间,只有宽度可以继承。*/
.wrap{
    width:300px;
}
.box2{
    height: 300px;
    background-color: blueviolet;
    border: 1px solid black;
    padding: 50px;
}

.box3 {
    width: 300px;
    box-sizing: border-box;
    /*将父盒子的宽度作用于边框上而不是内容上。*/
    background-color: blueviolet;
    border: 2px solid black;
    padding: 50px;
    /*作用到边框上,盒子不会撑开*/
}

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2.外边距:(1)同级塌陷(2)嵌套传递(3)自动挤压   同级塌陷只是上下塌陷,左右是重叠

实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx3.css">
    <title>margin外边距</title>
</head>
<body>
<!--1.同级塌陷-->
<!--2嵌套传递-->
<!--3.自动挤压-->


<!--1.同级塌陷-->
<div class="box1"></div>
<div class="box2"></div>

<hr>
<!--2嵌套传递-->
<div class="box3">
    <div class="box4"></div>
</div>
<hr>
<!--3.自动挤压-->
<div class="box5"></div>
</body>
</html>


.box1 {
     width: 100px;
     height: 100px;
     background-color: blueviolet;
 }
.box2 {
    width: 100px;
    height: 100px;
    background-color: red;
}
.box1{
    margin-bottom: 30px;
}
.box2{
    margin-bottom: 30px;
}
.box2{
    margin-top: 50px;
}
/*小的会塌陷到大的里面,已大的为准。左右叠加,上下塌陷*/

.box3 {
    width: 200px;
    height: 200px;
    background-color: yellowgreen;
}

.box4 {
    width: 100px;
    height: 100px;
    background-color: yellow;
}
.box4 {
    margin-top: 0px;
}
.box3 {
    padding-top: 30px;
    height: 170px;
}


.box5 {
    width: 100px;
    height: 100px;
    background-color: royalblue;
    margin-left: auto;
    margin-right: auto;
    margin: 50px auto;
}

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3.浮动:(1)文档流 html元素默认按照书写的顺序在浏览器中,遵循先从左到右、在从上到下的顺序。(2)布局前提:通常先将元素从文档流中脱离出来,这样才能按照自己的要求布局(3)布局手段:浮动和绝对定位。

清除浮动:clean:both;

实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx4.css">
    <title>浮动</title>
</head>
<body>
<!--1.文档流 html元素默认按照书写的顺序在浏览器中,遵循先从左到右、在从上到下的顺序。-->
<!--2.布局前提:通常先将元素从文档流中脱离出来,这样才能按照自己的要求布局-->
<!--3.布局手段:浮动和绝对定位。-->


<!--浮动的基本原理-->
<div class="box1"></div>
<div class="box2"></div>
<div class="box3"></div>
<div class="box4"></div>
</body>
</html>

box1 {
    width: 100px;
    height: 100px;
    background-color: royalblue;
}
.box2 {
    width: 150px;
    height: 150px;
    background-color: rosybrown;
}
/*元素浮动之后就脱离了文档流*/
.box1 {
    float: left;
}
.box2 {
    float: left;
}
.box3 {
    width:200px;
    height: 300px;
    background-color: tomato;
}
.box3 {
    float: right;
}

.box4 {
    width:100%;
    height: 50px;
    background-color: black;
}
.box4 {
    clear: left;
    clear: right;
}
.box4 {
    clear: both;
}

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4.定位:(1)静态定位: 浏览器默认方式, 即文档流中的位置(2)相对定位:元素并未脱离文档流,只是相对于它原来的位置,做相对移动(3)绝对定位: 元素脱离文档流重新排列,不论元素之前是什么类型,全部转为块元素,支持宽高(4)固定定位: 始终相对于浏览器的窗口做为定位父级,进行定位。相对定位是相对该元素自己原来的位置

实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx7.css">
    <title>php中文网登录页面</title>
</head>
<body>
<div class="shade"></div>
<div class="login" ><img src="static/images/login.jpg" alt=""></div>

</body>
</html>
body {
    margin: 0;
    background-image: url("../images/php.jpg");
    background-size: cover;
    background-repeat: no-repeat;
}
.shade {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: black;
    opacity: 0.7;
}
.login img{
    width: 380px;
    height: 460px;
    background-color: white;
    position: absolute;
    left: 50%;
    top:50%;
    margin-left: -190px;
    margin-top: -230px;

}

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实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx8.css">
    <title>固定定位</title>
    <!--相对于body-->
</head>
<!--相对定位是相对该元素自己原来的位置-->
<body>
<div class="ads">
    <button >x</button>
    <h2>php中文网开课啦</h2>
    <h3>招生进行中。。。</h3>
</div>

</body>
</html>

body {
    height: 2000px;
}
.ads {
    width: 300px;
    height: 300px;
    background-color: bisque;
    position: fixed;
    right: 0;
    bottom: 0;
}
.ads button {
    background-color: red;
}

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实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx5.css">
    <title>定位</title>
</head>
<body >
<!--relative相对,未脱离文档流,相对于body-->
<!--<div style="width: 100px;height: 100px;background-color: yellow;position: relative;top: 50px;left: 30px"></div>-->
<div class="box1">1</div>
<div class="box2">2</div>
<div class="box3">3</div>
<div class="box4">4</div>
<div class="box5">5</div>
</body>
</html>


.box1 {
    width: 100px;
    height: 100px;
    background-color: yellow;
}
.box2{
    width: 100px;
    height: 100px;
    background-color: red;
}
.box3 {
    width: 100px;
    height: 100px;
    background-color: darkviolet;
}
.box4 {
    width: 100px;
    height: 100px;
    background-color: green;
}
.box5 {
    width: 100px;
    height: 100px;
    background-color: palevioletred;
}
.box1 {
    position: relative;
    left: 100px;
}
.box3 {
    position: relative;
    left: 100px;
    top: -100px;
}
.box4 {
    position: relative;
    left: 200px;
    top: -200px;
}
.box5 {
    position: relative;
    left: 100px;
    top: -200px;
}

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实例

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <link rel="stylesheet" href="static/css/xxxx6.css">
    <title>定位</title>
</head>
<body  >
<!--relative相对,未脱离文档流,相对于body-->
<!--<div style="width: 100px;height: 100px;background-color: yellow;position: relative;top: 50px;left: 30px"></div>-->

<div class="parent">
    <div class="box1">1</div>
    <div class="box2">2</div>
    <div class="box3">3</div>
    <div class="box4">4</div>
    <div class="box5">5</div>
</div>




</body>
</html>

.parent {
    border: 1px dotted black;
    width: 300px;
    height: 300px;
}
.parent {
    position: relative;
}




.box1 {
    width: 100px;
    height: 100px;
    background-color: yellow;
}
.box2{
    width: 100px;
    height: 100px;
    background-color: red;
}
.box3 {
    width: 100px;
    height: 100px;
    background-color: darkviolet;
}
.box4 {
    width: 100px;
    height: 100px;
    background-color: green;
}
.box5 {
    width: 100px;
    height: 100px;
    background-color: palevioletred;
}
.box1 {
    position: absolute;
    left: 100px;
}
.box2 {
    position: absolute;
    top: 100px;
}
.box3 {
    position: absolute;
    left: 100px;
    top: 100px;
}
.box4 {
    position: absolute;
    left: 200px;
    top: 100px;
}
.box5 {
    position: absolute;
    top: 200px;
    left: 100px;
}

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Correction status:qualified

Teacher's comments:学习一定要有总结, 才会有进步
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