day 16 JS DOM 繼續

時間 2019-12-13

標籤 day dom 繼續欄目 JavaScript 简体版

原文原文鏈接

爲何有jquey了還學DOM ？

由於JQuey 是大而全，可能有10k 可是咱們用到的只有1k 網站小沒事，網站大流量就是問題

因此大網站都是本身用DOM 實現一個相似於JQuey 的適合本身公司的模塊

因此須要學習DOM 。

回顧下上次內容：

min-width 設置最小寬度，在頁面縮放的時候，當寬度小於指定寬度時，使用最小寬度css

左邊菜單不動 html

學一個新技能，只要改一個屬性就能實現菜單左邊固定不動和菜單隨右邊內容滾動python

實踐：函數

<!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;">返回頂部</div>-->
            <!--<div style="position: absolute;bottom:0;right:0;width: 50px;height: 50px;">返回頂部</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>

調整爲圓形的就調整這個參數爲50%學習

實踐：網站

<!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：spa

咱們如何使用第三方的圖標呢？htm

下載css庫，而後引用，直接使用就能夠了：對象

效果：blog

調整padding參數，變圓：

9 序列化

時間，就是一個類，有不少方法：

做用域：

就近原則，找變量，和python 同樣

聲明變量沒有賦值就是 undefined

解決每一個對象須要用共同的東西，可是又不想佔用更多內存的方法：

未解決前：

使用原形解決：

原形建立於類裏面這樣就不存在於對象中了

對html的操做：

操做：

1 使用text

2 使用html

操做文本框：

select 框：

查找分爲兩種形式：

select 特有的能夠經過 index 設置

大文本框的獲取及更改：

實現一個搜索框的默認有文字，鼠標點擊後文字消失的功能：

<!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="請輸入關鍵字"/>
    </div>
    <script>
        function Focus() {
            var tag = document.getElementById("i1");
            var val = tag.value;
            if(val == "請輸入關鍵字"){
                tag.value="";
            }
        }
        function Blur() {
            var tag = document.getElementById("i1");
            var val = tag.value;
            if(val.length == 0){
                tag.value="請輸入關鍵字";
            }
        }
    </script>
</body>
</html>

效果：

JavaScripts 函數通常用駝峯樣式寫

操做html 標籤：

第二種方法：

寫一個我的菜單的樣式效果：

<!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>個人資料</a>
                <a>註銷</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;">返回頂部</div>-->
            <!--<div style="position: absolute;bottom:0;right:0;width: 50px;height: 50px;">返回頂部</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：

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