day 16 JS DOM 继续

为什么有jquey了还学DOM ？

因为JQuey 是大而全，可能有10k 但是我们用到的只有1k 网站小没事，网站大流量就是问题

所以大网站都是自己用DOM 实现一个类似于JQuey 的适合自己公司的模块

所以需要学习DOM 。

回顾下上次内容：

min-width 设置最小宽度，在页面缩放的时候，当宽度小于指定宽度时，使用最小宽度

左边菜单不动

学一个新技能，只要改一个属性就能实现菜单左边固定不动和菜单随右边内容滚动

实践：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            margin: 0;
        }
        .left{
            float: left;
        }
        .right{
            float: right;
        }
        .pg-header{
            height: 48px;
            background-color: #2459a2;
            color: white;
        }
        .pg-content .menu{
            position: absolute;
            top:48px;
            left: 0;
            bottom: 0;
            width: 200px;
            background-color: #dddddd;
        }
        .pg-content .content{
            position: absolute;
            top: 48px;
            right: 0;
            bottom: 0;
            left: 200px;
            min-width: 980px;
            overflow: auto;
        }
    </style>
</head>
<body>
    <div class="pg-header"></div>
    <div class="pg-content">
        <div class="menu left">a</div>
        <div class="content left">
            <!--<div style="position: fixed;bottom:0;right:0;width: 50px;height: 50px;">返回顶部</div>-->
            <!--<div style="position: absolute;bottom:0;right:0;width: 50px;height: 50px;">返回顶部</div>-->
            <div style="background-color: purple">
            <p style="margin: 0;">asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p style="margin: 0;">asdf</p>
                </div>
        </div>
    </div>
    <div class="pg-footer"></div>
</body>
</html>

调整为圆形的就调整这个参数为50%

实践：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        .item{
            background: #dddddd;
        }
        .item:hover{
            color: red;
        }
        .item:hover .b{
            background-color: #396bb3;
        }
    </style>
</head>
<body>
    <div class="item">
        <div class="a">aa</div>
        <div class="b">bb</div>
    </div>
</body>
</html>

效果：

我们如何使用第三方的图标呢？

下载css库，然后引用，直接使用就可以了：

效果：

调整padding参数，变圆：

9 序列化

时间，就是一个类，有很多方法：

作用域：

就近原则，找变量，和python 一样

声明变量没有赋值就是 undefined

解决每个对象需要用共同的东西，但是又不想占用更多内存的方法：

未解决前：

使用原形解决：

原形创建于类里面这样就不存在于对象中了

对html的操作：

操作：

1 使用text

2 使用html

操作文本框：

select 框：

查找分为两种形式：

select 特有的可以通过 index 设置

大文本框的获取及更改：

实现一个搜索框的默认有文字，鼠标点击后文字消失的功能：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div style="width: 600px; margin: 0 auto">
        <input type="text" id="i1" onfocus="Focus();"  onblur="Blur();" value="请输入关键字"/>
    </div>
    <script>
        function Focus() {
            var tag = document.getElementById("i1");
            var val = tag.value;
            if(val == "请输入关键字"){
                tag.value="";
            }
        }
        function Blur() {
            var tag = document.getElementById("i1");
            var val = tag.value;
            if(val.length == 0){
                tag.value="请输入关键字";
            }
        }
    </script>
</body>
</html>

效果：

JavaScripts 函数一般用驼峰样式写

操作html 标签：

第二种方法：

写一个个人菜单的样式效果：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            margin: 0;
        }
        .left{
            float: left;
        }
        .right{
            float: right;
        }
        .pg-header{
            height: 48px;
            background-color: #2459a2;
            color: white;
            line-height: 48px;
        }
        .pg-header .logo{
            width: 200px;
            background-color: cadetblue;
            text-align: center;
        }
        .pg-header .user{
                margin-right: 60px;
            padding: 0 20px;
            color: white;
            height: 48px;
        }
        .pg-header .user:hover{
            background-color: #204982;
        }
        .pg-header .user .a img{
            height: 40px;width: 40px;margin-top: 4px;border-radius: 50%;
        }
        .pg-header .user .b{
                z-index: 20;
                position: absolute;
                top: 48px;
                right: 44px;
                background-color: white;
            color: black;
            width: 160px;
            display: none;
        }
        .pg-header .user:hover .b{
            display: block;
        }
        .pg-header .user .b a{
            display: block;
        }
        .pg-content .menu{
            position: absolute;
            top:48px;
            left: 0;
            bottom: 0;
            width: 200px;
            background-color: #dddddd;
        }

        .pg-content .content{
            position: absolute;
            top: 48px;
            right: 0;
            bottom: 0;
            left: 200px;
            overflow: auto;
            z-index: 9;

        }
    </style>
</head>
<body>

    <div class="pg-header">
        <div class="logo left">
            老男孩
        </div>
        <div class="user right" style="position: relative">
            <a class="a" href="#">
                <img src="22.jpg">
            </a>
            <div class="b">
                <a>我的资料</a>
                <a>注销</a>
            </div>
        </div>


    </div>
    <div class="pg-content">
        <div class="menu left">a</div>
        <div class="content left">
            <!--<div style="position: fixed;bottom:0;right:0;width: 50px;height: 50px;">返回顶部</div>-->
            <!--<div style="position: absolute;bottom:0;right:0;width: 50px;height: 50px;">返回顶部</div>-->
            <div style="background-color: purple">
            <p style="margin: 0;">asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
            <p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p><p>asdf</p>
                </div>
        </div>
    </div>
    <div class="pg-footer"></div>
</body>
</html>

效果：

posted @ 2016-11-29 14:33 yangever 阅读(255) 评论(0) 编辑收藏举报

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day 16 JS DOM 继续

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