margin层叠情况，及表现-前端--易笔记

1.上下/左右相邻的普通元素margin，不是两者相加之和，而是取最大值，这个现象叫做margin重叠。

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>用p来占布局</title>
  <script type="text/javascript" src="https://www3.lenovo.com/_ui/desktop/common/js/jquery/jquery-1.11.2.min.js"></script>
  <style>
    .p1,.p2{
        width:100px;
        height:100px;
        background-color:red;
        margin:20px;
        /*float:left;
        clear:left;*/
    }

  </style>
 </head>

 <body>
    <p class="p1"></p>
    <p class="p2"></p>
    <script>

    </script>
 </body>
</html>

2.普通元素才会发生margin重叠，如果是float元素，就不会发生。margin是两者相加之和

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>用p来占布局</title>
  <script type="text/javascript" src="https://www3.lenovo.com/_ui/desktop/common/js/jquery/jquery-1.11.2.min.js"></script>
  <style>
    .p1,.p2{
        width:100px;
        height:100px;
        background-color:red;
        margin:20px;
        float:left;
        clear:left;
    }

  </style>
 </head>

 <body>
    <p class="p1"></p>
    <p class="p2"></p>
    <script>

    </script>
 </body>
</html>

3.父子元素，无浮动，发生重叠

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>用p来占布局</title>
  <script type="text/javascript" src="https://www3.lenovo.com/_ui/desktop/common/js/jquery/jquery-1.11.2.min.js"></script>
  <style>
    .father{
        width:400px;
        height:400px;
        background-color:gray;
        margin:20px;
    }
    .child1{
        width:100px;
        height:100px;
        background-color:red;
        margin:20px;
        /*float:left;*/
    }
    .child2{
        width:100px;
        height:100px;
        background-color:red;
        margin:30px;
        /*float:left;*/
    }
  </style>
 </head>

 <body>
    <p class="father">
        <p class="child1"></p>
        <p class="child2"></p>
    </p>

    <script>

    </script>
 </body>
</html>

margin层叠情况，及表现

4.父子元素，无浮动，发生重叠

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "https://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <title>用p来占布局</title>
  <script type="text/javascript" src="https://www3.lenovo.com/_ui/desktop/common/js/jquery/jquery-1.11.2.min.js"></script>
  <style>
    .father{
        width:400px;
        height:400px;
        background-color:gray;
        margin:20px;
    }
    .child1{
        width:100px;
        height:100px;
        background-color:red;
        margin:20px;
        float:left;
    }
    .child2{
        width:100px;
        height:100px;
        background-color:red;
        margin:30px;
        float:left;
    }
  </style>
 </head>

 <body>
    <p class="father">
        <p class="child1"></p>
        <p class="child2"></p>
    </p>

    <script>

    </script>
 </body>
</html>

时间：2017/1/20 9:53:09