Bootstrap

h5的相对定位、绝对定位、固定定位以及案例练习

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <style>
        #right,#left,#center{
            float: left;
        }
        #left{
            width: 200px;
            height: 200px;
            background-color: yellow;
        }
        #center{
            width: 200px;
            height: 200px;
            background-color: #cccccc;
            /*position: relative;*/
            position: absolute;
            top: 20px;
            left: 20px;
            /*z-index 可以改变浮动的布局
              z-index可以在相对和绝对定位中使用*/
            z-index: -1;
        }
        #right{
            width: 200px;
            height: 200px;
            background-color: aquamarine;
        }
    </style>
    <title>定位</title>
</head>
<body>
<!--css定位属性position
    static
    relative 相对定位
    absolute 绝对定位
    fixed 固定定位-->
<!--css其他定位属性
    top
    right
    bottom
    left
    Z-index-->
<!--相对定位是相对于元素的原始位置,移动后仍然占据原来的位置-->
<!--绝对定位是相对于最近的定位父元素进行定位。定位后,原来的位置会被其他元素补充(定位后他的位置会空出来)
     采用绝对定位的元素,会寻找离他最近的采用了定位的父元素,并以其为坐标进行定位
     若所有父元素都没使用定位,则以body为坐标进行定位-->
<!--固定定位类似于绝对定位,根据窗口原点进行偏移定位,不会根据滚动条的滚动进行偏移-->
<div style="position: relative;top: 50px;left: 100px">
    <div>
        <div id="left"></div>
        <div id="center"></div>
        <div id="right"></div>
    </div>
</div>
</body>
</html>
书签式界面的方法线、点、方框全是图片
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <style>
        .biao{
            position: relative;
            height: 700px;
            width: 1011px;
            background-color:darkgrey;
        }
        .shu{
            position: absolute;
            width: 1px;
            height: 658px;
            background-image: url("../../img/f1_line.png");
            left: 505px;
            top: 21px;
        }
        .dian1{
            background-image: url("../../img/f1_dot.png");
            position: absolute;
            width: 18px;
            height: 18px;
            top: 20px;
            left: -8.5px;
        }
        .tu1{
            background-image: url("../../img/f1_2016.png");
            position: absolute;
            width: 480px;
            height: 167px;
            left: -481px;
            top: -16px;

        }
        .dian2 {
            background-image: url("../../img/f1_dot.png");
            position: absolute;
            width: 18px;
            height: 18px;
            top: 60px;
            left: -8.5px;
        }
        .tu2{
            background-image: url("../../img/f1_2015.png");
            position: absolute;
            width: 480px;
            height: 167px;
            left:18px;
            top: -15px;

        }
        .dian3{
            background-image: url("../../img/f1_dot.png");
            position: absolute;
            width: 18px;
            height: 18px;
            top: 220px;
            left: -8.5px;
        }
        .tu3{
            background-image: url("../../img/f1_2014.png");
            position: absolute;
            width: 480px;
            height: 167px;
            left: -481px;
            top: -16px;

        }
        .dian4{
            background-image: url("../../img/f1_dot.png");
            position: absolute;
            width: 18px;
            height: 18px;
            top: 260px;
            left: -8.5px;
        }
        .tu4{
            background-image: url("../../img/f1_2013.png");
            position: absolute;
            width: 480px;
            height: 167px;
            left:18px;
            top: -15px;

        }
        .dian5{
            background-image: url("../../img/f1_dot.png");
            position: absolute;
            width: 18px;
            height: 18px;
            top: 420px;
            left: -8.5px;
        }
        .tu5{
            background-image: url("../../img/f1_2012.png");
            position: absolute;
            width: 480px;
            height: 167px;
            left: -481px;
            top: -16px;

        }
        .dian6{
            background-image: url("../../img/f1_dot.png");
            position: absolute;
            width: 18px;
            height: 18px;
            top: 460px;
            left: -8.5px;
        }
        .tu6{
            background-image: url("../../img/f1_2011.png");
            position: absolute;
            width: 480px;
            height: 167px;
            left:18px;
            top: -15px;

        }
    </style>
    <title>书签</title>
</head>
<body>
<div class="biao">
    <div class="shu">
        <div class="dian1">
            <div class="tu1"></div>
        </div>
        <div class="dian2">
            <div class="tu2"></div>
        </div>
        <div class="dian3">
            <div class="tu3"></div>
        </div>
        <div class="dian4">
            <div class="tu4"></div>
        </div>
        <div class="dian5">
            <div class="tu5"></div>
        </div>
        <div class="dian6">
            <div class="tu6"></div>
        </div>
    </div>
</div>
</body>
</html>
固定定位的运用
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <style>
        #back{
            width: 150px;
            background-color: #4d2e83;
            height: 50px;
            text-align: center;
            line-height: 50px;
            position: fixed;
            bottom: 50px;
            right: 50px;
            /*z-index 一般设置为一个极大的数值 数字越大越在前*/
            z-index: 1000;

        }
    </style>
    <title>固定定位</title>
</head>
<body>
<div style="height: 2000px">
    <div id="back">
        返回i页面顶部
    </div>
</div>
</body>
</html>

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