javascript

1.js引入方式

1.1引入方式一：內(nèi)接式

<script type="text/javascript">
        var a=3
        document.write(a)
    </script>

1.2引入方式二：外接式

<script type="text/javascript" src="index.js"></script>

2.注釋

//單行注釋

3.調(diào)試語句

alert('');彈出警告框
console.log('');控制臺(tái)輸出
document.write('');頁面上輸出

4.變量

4.1定義變量

//方式一：先定義  后賦值
var a=3;
a=100;

//方式二：定義+賦值
var a=100;

//變量需要先定義，后使用，不設(shè)置變量，直接輸出，會(huì)報(bào)錯(cuò)

<script type="text/javascript">
        var a1=3;
        var a2=100;
        console.log("a1---",a1)
        console.log("a2---",a2)
        console.log("a3---",a3)
    </script>

4.2變量的命名規(guī)范

只能由英文字母、數(shù)字、下劃線、美元符號(hào)$構(gòu)成
不能以數(shù)字開頭
不能是js的關(guān)鍵字

4.3數(shù)值類型-number

如果一個(gè)變量中，存放了數(shù)字，那么這個(gè)變量就是數(shù)值類型
只要是數(shù)字，無論是整數(shù)，還是小數(shù)，無論正數(shù)，負(fù)數(shù)
typeof number;//查看數(shù)據(jù)類型

<script type="text/javascript">
        var a1 = 3;
        var a2 = 3.232;
        var a3 = -3.2;
        var a4 = 5/0;//Infinity 無限大
        var a5 = '23';
        console.log("var a1=3---",typeof a1);
        console.log("var a2=3.232---",typeof a2);
        console.log("var a3 = -3.2---",typeof a3);
        console.log("var a4 = 5/0---",typeof a4);
        console.log("var a5 = '23'---",typeof a5);
    </script>

4.4字符串類型-string

<script type="text/javascript">
        var a1 = 'a1';
        var a2 = '3.232';
        var a3 = '-3.2';
        var a4 = '5/0';
        var a5 = '23';
        var a6 = '';//空字符串
        var a7 = "wo就是\"任性\"的'小美女";//單引號(hào)，雙引號(hào)都有，使用\轉(zhuǎn)義
        var a8 = "wo"+"愛"+"拼接";//拼接
        var a9 = "wo+愛+拼接";//原樣輸出
        console.log("var a1='3'---",typeof a1);
        console.log("var a2='3.232'---",typeof a2);
        console.log("var a3 = '-3.2'---",typeof a3);
        console.log("var a4 = '5/0'---",typeof a4);
        console.log("var a5 = '23'---",typeof a5);
        console.log("var a6 = ''---",typeof a6);
        console.log("var a7 = \"wo就是\\\"任性\\\"的'小美女\"---",typeof a7);
        console.log("var a8 = \"wo\"+\"愛\"+\"拼接\"----",a8);
        console.log("var a9 = \"wo+愛+拼接\"----",a9);
    </script>

4.5布爾類型-boolean

<script type="text/javascript">
        var a1 = true;
        var a2 = false;
        console.log("var a1 = true---",typeof a1);
        console.log("var a2 = false---",typeof a2);

    </script>

4.6空對象-object

<script type="text/javascript">
        var a1 = null;
        console.log("var a1 = null---",typeof a1);

    </script>

4.7未定義-undefined

<script type="text/javascript">
        var a1;
        console.log("var a1---",typeof a1);

    </script>

4.8復(fù)雜數(shù)據(jù)類型

Fuction
Object
Array
String
Date
后面詳解

4.9數(shù)據(jù)類型轉(zhuǎn)換

4.9.1number轉(zhuǎn)換為string類型

//隱式轉(zhuǎn)換
<script type="text/javascript">
        var n1 = 123;
        var n2 = '123';
        var n3 = n1+n2;
        // 隱式轉(zhuǎn)換
        console.log(typeof n3);

    </script>

//強(qiáng)制轉(zhuǎn)換
<script type="text/javascript">
        var n1 = 123;
        // 強(qiáng)制轉(zhuǎn)換
        console.log("String(n1)",typeof String(n1));
        console.log("n1.toString()",typeof n1.toString());

    </script>

//四舍五入
<script type="text/javascript">
        var num = 132.32522;
        console.log(num.toFixed(2));
    </script>

4.9.2string轉(zhuǎn)換為number類型

<script type="text/javascript">
        var n1 = "123";
        // 強(qiáng)制轉(zhuǎn)換
        console.log("n1",n1);
        console.log("Number(n1)",typeof Number(n1));
        console.log("parseInt(n1)",typeof parseInt(n1));

        var stringNUm = '789.123wewe';
        console.log("stringNUm ",stringNUm);
        console.log('Number(stringNUm)',Number(stringNUm));//NaN   Not a Number
        //parseInt()可以解析一個(gè)字符串，并返回一個(gè)整數(shù)
        console.log("parseInt(stringNUm)",parseInt(stringNUm));
        console.log("parseFloat(stringNUm)",parseFloat(stringNUm));
    </script>

4.9.3任何數(shù)據(jù)類型都可以轉(zhuǎn)為boolean類型

var b1 = '123'; //true
var b2 = 0; //false
var b3 = -123 //true
var b4 = Infinity; //true
var b5 = NaN; //false
var b6; //false
var b7 = null; //false
//使用Boolean(變量) 來查看當(dāng)前變量的真假

5.運(yùn)算符

5.1賦值運(yùn)算符

5.2算數(shù)運(yùn)算符

5.3比較運(yùn)算符

6.流程控制

6.1if

var age = 20;
if(age>18){
    //{}相當(dāng)于作用域
    console.log('可以去學(xué)車');
}
alert('vita'); //下面的代碼照樣執(zhí)行

6.2if-else

var age = 20;
if(age>18){
    //{}相當(dāng)于作用域
    console.log('可以去學(xué)成');
}else{
    console.log('年齡還不到');
}
alert('vita'); //下面的代碼照樣執(zhí)行

6.3if-else if -else

var age = 18;
if(age==18){
    //{}相當(dāng)于作用域
    console.log('可以去學(xué)成');
}else if(age==30){
    console.log('該買車了');
}else{
    console.log('隨便你了')
}
alert('vita'); //下面的代碼照樣執(zhí)行

6.4邏輯與&&、邏輯或||

//1.模擬  如果總分 >400 并且數(shù)學(xué)成績 >89分 被**大學(xué)錄入
//邏輯與&& 兩個(gè)條件都成立的時(shí)候 才成立
if(sum>400 && math>90){
    console.log('**大學(xué)錄入成功');
}else{
    alert('去別的學(xué)校吧');
}

//2.模擬 如果總分>500 或者你英語大于85 被**大學(xué)錄入
//邏輯或  只有有一個(gè)條件成立的時(shí)候 才成立
if(sum>500 || english>85){
    alert('被**大學(xué)錄入');
}else{
    alert('去別的學(xué)校吧');
}

6.5switch語句

<script type="text/javascript">
        var gameScore = 'better';

        switch(gameScore){

        //case表示一個(gè)條件 滿足這個(gè)條件就會(huì)走進(jìn)來 遇到break跳出。break終止循環(huán)。
            case 'good':
            console.log('玩的很好');
            //break表示退出
            break;
            case  'better':
            console.log('玩的超級厲害了');
            break;
            case 'best':
            console.log('恭喜你 吃雞成功');
            break;
            default:
            console.log('很遺憾')

        }
        //注意：switch相當(dāng)于if語句 但是玩switch的小心case穿透
        //如果某個(gè)條件中不寫 break，那么直到該程序遇到下一個(gè)break停止
    </script>

6.6while循環(huán)

<script type="text/javascript">
        // 例子：打印 1~9之間的數(shù)
        var i = 1; //初始化循環(huán)變量

        while(i<=9){ //判斷循環(huán)條件
            console.log(i);
            i = i+1; //更新循環(huán)條件
        }
    </script>

6.7do-while循環(huán)

用途不大：就是先做一次 ，上來再循環(huán)
<script type="text/javascript">
        //不管有沒有滿足while中的條件do里面的代碼都會(huì)走一次
        var i = 3;//初始化循環(huán)變量
        do{

            console.log(i);
            i++;//更新循環(huán)條件

        }while (i<10) //判斷循環(huán)條件
    </script>

6.8for循環(huán)

    <script type="text/javascript">
        //輸出1~10之間的數(shù)
        for(var i = 1;i<=10;i++){
             console.log(i);
         }
    </script>

7.函數(shù)

function：是關(guān)鍵字。
函數(shù)名字：命名規(guī)定和變量的命名規(guī)定一樣。
    只能是字母、數(shù)字、下劃線、美元$符號(hào)，不能以數(shù)字開頭。
參數(shù)()：后面有一對小括號(hào)，里面放參數(shù)。
大括號(hào){}里面是函數(shù)語句

<script type="text/javascript">
        function add(x,y) {
            return x+y;
        }
        console.log(add(1,2));
    </script>

7.1函數(shù)全局污染

兩個(gè)js文件中的函數(shù)名相同，會(huì)調(diào)用后引入的js中的函數(shù)

7.2全局污染處理

8.對象

8.1創(chuàng)建對象的方式

1.使用Object或?qū)ο笞置媪縿?chuàng)建對象
2.工廠模式創(chuàng)建對象
3.構(gòu)造函數(shù)模式創(chuàng)建對象
4.原型模式創(chuàng)建對象

8.2使用Object或?qū)ο笞置媪縿?chuàng)建對象

object方式創(chuàng)建對象
<script type="text/javascript">
        var student = new Object();
        student.name = 'easy';
        student.age = 20;
        console.log(student)
    </script>

字面量方式創(chuàng)建對象
<script type="text/javascript">
        var student = {
            name:'easy',
            age:20
        }
        console.log(student)
    </script>

一個(gè)student對象創(chuàng)建完成，擁有兩個(gè)屬性:name及age。
但這種方式有個(gè)缺點(diǎn)，就是創(chuàng)建多個(gè)student,就需要書寫多次相同模式的代碼。

8.2.1對象取值小方法

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>

</head>
<body>
<p id="active">p標(biāo)簽內(nèi)容--原有內(nèi)容</p>
<div id="box">

</div>
<input type="button" value="按鈕">

    <script type="text/javascript">
        var o = {a:{"name":"vita1"},b:{"name":"vita2"},c:{"name":"vita3"},d:{"name":"vita4"}};
        for(var name in o){
            console.log(name + ':' + o[name]["name"]);
        }

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

8.2.2刪除對象中的屬性

<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>

</head>
<body>
<p id="active">p標(biāo)簽內(nèi)容--原有內(nèi)容</p>
<div id="box">

</div>
<input type="button" value="按鈕">

    <script type="text/javascript">
        var o = {a:{"name":"vita1"},b:{"name":"vita2"},c:{"name":"vita3"},d:{"name":"vita4"}};
        for (var item in o){
                //刪除對象中的屬性
            delete o[item];

        }
        console.log(o)

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

8.3工廠模式創(chuàng)建對象

<script type="text/javascript">

        function student(name,age) {
            var student_obj = new Object();
            student_obj.name=name;
            student_obj.age=age;
            return student_obj;
        }

        var student1 = student("student1",22);
        var student2 = student("student2",22);
        console.log("student1",student1)
        console.log("student1 ×××tanceof Object",student1 ×××tanceof Object)
        console.log("student2",student2)
        console.log("student2 ×××tanceof Object",student2 ×××tanceof Object)
    </script>

<script type="text/javascript">

        function student(name,age) {
            var student_obj = new Object();
            student_obj.name=name;
            student_obj.age=age;
            return student_obj;
        }
        function fruit(name,color) {
            var fruit_obj = new Object();
            fruit_obj.name = name;
            fruit_obj.color = color;
            return fruit_obj;
        }

        var student1 = student("student1",22);
        var fruit = fruit("香蕉","×××")
        console.log("student1",student1)
        console.log("student1 ×××tanceof Object",student1 ×××tanceof Object)
        console.log("fruit",fruit)
        console.log("ruit ×××tanceof Object",fruit ×××tanceof Object)
    </script>

對于上面創(chuàng)建的對象student1和fruit，用×××tanceof監(jiān)測，都是Object類型
如果我們希望student1是student類型，fruit是fruit類型，那么可以使用自定義構(gòu)造函數(shù)的方法來創(chuàng)建對象。

8.4構(gòu)造函數(shù)模式創(chuàng)建對象

8.4.1構(gòu)造函數(shù)和普通函數(shù)

var obj = new Object();
var arr = new Array(10);  //構(gòu)造一個(gè)初始長度為10的數(shù)組對象
這兩種都是使用構(gòu)造函數(shù)方式創(chuàng)建對象

構(gòu)造函數(shù)與普通函數(shù)區(qū)別：
1.實(shí)際上并不存在創(chuàng)建構(gòu)造函數(shù)的特殊語法。
對于任意函數(shù)，使用new操作符調(diào)用，就是構(gòu)造函數(shù)；不使用new操作符調(diào)用，就是普通函數(shù)。
2.按照慣例，約定構(gòu)造函數(shù)名以答謝字母開頭，普通函數(shù)以小寫字母開頭。例如new Array()，new Object()。
3.使用new操作符調(diào)用構(gòu)造函數(shù)時(shí)，會(huì)經(jīng)歷(1)創(chuàng)建一個(gè)新對象；(2)將構(gòu)造函數(shù)作用域賦給新對象（使this指向該新對象）；(3)執(zhí)行構(gòu)造函數(shù)代碼；(4)返回新對象；4個(gè)階段。

8.4.2構(gòu)造函數(shù)創(chuàng)建對象

    <script type="text/javascript">

        function Student(name,age) {
            this.name = name;
            this.age = age;
            this.alertName=function () {
                alert(this.name);
            }
        }
        function Fruit(name,color) {
            this.name = name;
            this.color = color;
            this.alertName = function () {
                alert(this.name);
            }
        }

        var student1 = new Student("student1",22);
        var fruit1 = new Fruit("香蕉","×××")
        console.log("student1",student1);
        console.log("fruit1",fruit1);

        alert(student1 ×××tanceof Student);  //true
        alert(fruit1 ×××tanceof Student);  //false
        alert(student1 ×××tanceof Fruit);  //false
        alert(fruit1 ×××tanceof Fruit);  //true

        alert(student1 ×××tanceof Object);  //true 任何對象均繼承自O(shè)bject
        alert(fruit1 ×××tanceof Object);  //true 任何對象均繼承自O(shè)bject
    </script>

我們看到兩個(gè)對象中有相同的方法，可以把相同的方法移到構(gòu)造函數(shù)外部

<script type="text/javascript">
        function alertName() {
            alert(this.name);
        }
        function Student(name,age) {
            this.name = name;
            this.age = age;
            this.alertName=alertName()
        }
        function Fruit(name,color) {
            this.name = name;
            this.color = color;
            this.alertName = alertName()

        }

        var student1 = new Student("student1",22);
        var fruit1 = new Fruit("香蕉","×××")
        console.log("student1",student1);
        console.log("fruit1",fruit1);

        alert(student1 ×××tanceof Student);  //true
        alert(fruit1 ×××tanceof Student);  //false
        alert(student1 ×××tanceof Fruit);  //false
        alert(fruit1 ×××tanceof Fruit);  //true

        alert(student1 ×××tanceof Object);  //true 任何對象均繼承自O(shè)bject
        alert(fruit1 ×××tanceof Object);  //true 任何對象均繼承自O(shè)bject
    </script>

我們通過將共用的函數(shù)定義為全局函數(shù)，這樣對象中的alertName屬性則被設(shè)置為指向該全局函數(shù)的指針。由此解決了內(nèi)存浪費(fèi)的問題。
還可以通過原型對象模式來解決

8.4.3原型模式創(chuàng)建對象

    <script type="text/javascript">
        function Student() {
            this.name = 'easy';
            this.age = 20;
        }

        Student.prototype.alertName = function(){
            alert(this.name);
        };

        var stu1 = new Student();
        var stu2 = new Student();

        stu1.alertName();  //easy
        stu2.alertName();  //easy

        alert(stu1.alertName == stu2.alertName);  //true 二者共享同一函數(shù)
    </script>

9.復(fù)雜數(shù)據(jù)類型

9.1數(shù)組Array

9.1.1數(shù)組的創(chuàng)建

方式一：字面量方式創(chuàng)建
<script type="text/javascript">
        var colors = ['green',123,{},true]
        console.log(colors)
    </script>

方式二：構(gòu)造函數(shù)方式
<script type="text/javascript">
        var colors = new Array()
        colors[0] = 'green'
        colors[1] = {}
        colors[2] = 123
        console.log(colors)
    </script>

7.1.2數(shù)組的常用方法

7.1.2.1toString()把數(shù)組轉(zhuǎn)換為字符串

<script type="text/javascript">
        var arr = [1,2,3];
        var a=arr.toString();//這種方法常用，通用于國際
        var b = arr.toLocaleString();//這種方法不常用，是顯示為本地的方式
        console.log(a)
        console.log(b)
    </script>

7.1.2.2重寫toString()和toLocalString()

<script type="text/javascript">
        var person1 = {
            toLocaleDateString:function () {
                return '隔壁老王';
            },
            toString:function () {
                return '隔壁老李';
            }
        };
        var people = [person1];
        console.log(people)
        console.log(person1.toString())
        console.log(person1.toLocaleDateString())
    </script>

7.1.2.3棧方法--后進(jìn)先出push()，pop()

<script type="text/javascript">
        var colors = ['green','red'];
        console.log("colors:",colors);
        colors.push('yellow');//往數(shù)組的最后添加項(xiàng)
        console.log("colors.push('yellow')",colors);
        colors.pop();//刪除數(shù)組的最后項(xiàng)
        console.log("colors.pop()",colors)
    </script>

7.1.2.4隊(duì)列方法-先進(jìn)先出unshif(),shift()

<script type="text/javascript">
        var colors = ['green','red'];
        console.log("colors:",colors);
        colors.unshift('yellow');//往數(shù)組的第一項(xiàng)添加數(shù)據(jù)
        console.log("colors.unshift('yellow')",colors);
        colors.shift();//刪除數(shù)組的第一項(xiàng)
        console.log("colors.shift()",colors)
    </script>

7.1.2.5數(shù)組排序sort(),reverse()

"sort是先按照第一個(gè)字符進(jìn)行排序，然后按照第二個(gè)字符排序"

<script type="text/javascript">
        var num = [1,3,20,9,7,4,29,35];
        console.log(num)
        console.log("num.sort()",num.sort());
        console.log("num.reverse()",num.reverse());
    </script>

"重寫sort排序規(guī)則"

<script type="text/javascript">
        var num = [1,3,20,9,7,4,29,35];
        function compare(a,b){
            if (a>b){
                return 1;
            }else if(a<b){
                return -1;
            }else {
                return 0;
            }
            //簡寫
            //return a-b;
        }
        console.log(num)
        console.log("num.sort()",num.sort(compare));
    </script>

7.1.2.6concat()把幾個(gè)數(shù)組合并為一個(gè)數(shù)組

<script type="text/javascript">
        var colors = ['red','yellow'];
        console.log("colors",colors);

        new_color = colors.concat('green');
        console.log("colors.concat('green')",new_color);
        new_color2 = colors.concat({name:'張三',age:23},['list1','list2']);
        console.log("colors.concat({name:'張三',age:23},['list1','list2'])",new_color2);
    </script>

7.1.2.7slice()數(shù)組切片

<script type="text/javascript">
        var colors = ['red','yellow',{name:'張三',age:23},'list1','list2'];
        console.log("colors",colors);

        new_colors = colors.slice(-2,-1);//slice(起始位置，結(jié)束位置)，顧頭不顧尾5-1,5-2---slice(3,4)
        console.log(new_colors)
    </script>

7.1.2.8splice()可插入，刪除，替換數(shù)組內(nèi)容

<script type="text/javascript">
        var colors = ['red','yellow',{name:'張三',age:23},'list1','list2'];
        console.log("colors",colors);
        //1.刪除
        colors.splice(0,2);//splice(start，deleteCount)
        console.log("colors.splice(0,2)",colors);
        //2.插入
        colors.splice(1,0,'熊大','熊二');
        console.log("colors.splice(1,0,'熊大','熊二')",colors);
        //3.替換
        colors.splice(1,1,'光頭強(qiáng)來也');
        console.log("colors.splice(1,1,'光頭強(qiáng)來也')",colors)
    </script>

7.1.2.9indexOf()，lastindexOf()查看數(shù)組中元素的索引

<script type="text/javascript">
        var colors = ['red','光頭強(qiáng)',{name:'張三',age:23},'熊大','red','熊二'];
        console.log("colors.indexOf('red')",colors.indexOf('red'));
        console.log("colors.lastIndexOf('red')",colors.lastIndexOf('red'));
        console.log("colors.indexOf('red',2)",colors.indexOf('red',2));//從索引2開始，查找red
        console.log("colors.lastIndexOf('red',2)",colors.lastIndexOf('red',2));
        console.log("colors.lastIndexOf('reddddd')",colors.lastIndexOf('reddddd'));//查不到結(jié)果，返回-1
    </script>

7.1.2.10filter()將數(shù)據(jù)中的元素進(jìn)行過濾

<script type="text/javascript">
        var numbers = [1,23,15];
        var filterResult = numbers.filter(function (item,index,array) {
            console.log("item",item);
            console.log("index",index);
            console.log("array",array);
            return item>10;

        });
        console.log("filterResult",filterResult);
    </script>

7.1.2.11map()對數(shù)組中的每個(gè)元素進(jìn)行操作

<script type="text/javascript">
        var numbers = [1,23,15];
        var mapResult = numbers.map(function (item,index,array) {
            return item*2;

        });
        console.log("mapResult",mapResult);
    </script>

7.1.2.12forEach()

<script type="text/javascript">
        var numbers = [1,23,15];

        numbers.forEach(function (item,index) {
            console.log(item)
        })
    </script>

7.1.2.13join()

將數(shù)組中元素使用指定的字符串連接起來，會(huì)形成一個(gè)新的字符串

<script type="text/javascript">
        var numbers = [1,23,15];

        new_numbers = numbers.join('|');
        console.log(new_numbers)
    </script>

7.1.2.14isArray(被檢測的值)

布爾類型值 = Array.isArray(被檢測的值) ;
判斷被檢測的值是否是數(shù)組，返回布爾值。

<script type="text/javascript">
        var numbers = [1,23,15];
        console.log(Array.isArray(numbers))
    </script>

7.1.3偽數(shù)組arguments

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        function fn(a,b,c) {
            console.log("arguments",arguments);
            console.log("fn.length",fn.length);//獲取形參個(gè)數(shù)
            console.log("arguments.length",arguments.length);//獲取實(shí)參個(gè)數(shù)
        }
        fn(2,4);
        fn(2,4,6);
        fn(2,4,6,8);
    </script>
</head>
<body>
</body>
</html>

之所以說arguments是偽數(shù)組，是因?yàn)閍rguments可以修改元素，但是不能改變數(shù)組的長度。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        function fn(a,b,c) {
            arguments[0]=99;//可以修改元素
            //arguments.push(8); 該方法不能通過，無法添加新元素
            console.log("arguments",arguments);
            console.log("fn.length",fn.length);//獲取形參個(gè)數(shù)
            console.log("arguments.length",arguments.length);//獲取實(shí)參個(gè)數(shù)
        }
        fn(2,4);
        fn(2,4,6);
        fn(2,4,6,8);
    </script>
</head>
<body>
</body>
</html>

7.2字符串

<script type="text/javascript">
        var str = 'hello world';
        console.log("str",str);
        console.log("str.length:",str.length);//獲取字符串的長度
        console.log("str.charAt(1):",str.charAt(1));//獲取指定的字符
        console.log("str.charCodeAt(1):",str.charCodeAt(1));//獲取指定字符對應(yīng)的編碼
        console.log("str.concat('vita','lili'):",str.concat('vita','lili'));//拼接字符串 通常情況下，不用這種方法拼接，使用+來做多個(gè)字符的拼接
        console.log("str.indexOf('o'):",str.indexOf('o'));
        console.log("str.lastIndexOf('o'):",str.lastIndexOf('o'));
        console.log("str.indexOf('o',6):",str.indexOf('o',6));
        console.log("str.lastIndexOf('o',6):",str.lastIndexOf('o',6));
        console.log("str.lastIndexOf('l',6):",str.lastIndexOf('l',6));//實(shí)際是從0-6這些字符串中，找出最后一個(gè)'l'
        console.log("str.replace('o',\"O\"):",str.replace('o',"O"));//僅僅把第一個(gè)o替換為了O
        console.log("str.search(\"wo\"):",str.search("wo"));
        console.log("str.slice(2,4):",str.slice(2,4));//從start 到end之間的字符，顧頭不顧尾
        console.log("str.split('o',2):",str.split('o',2));//以o分隔，獲取指定長度的數(shù)組
        console.log("str.substr(2,3):",str.substr(2,3));//第一個(gè)參數(shù)是start,第二個(gè)參數(shù)是length
        console.log("str.toUpperCase():",str.toUpperCase());
        console.log("str.toLowerCase()",str.toLowerCase());
        var str1 = '  hello world  ';
        console.log("str1",str1);
        console.log("str1.trim():",str1.trim());//清除當(dāng)前字符串前后的空格
    </script>

    <script type="text/javascript">
        var str = 'he unfoled the map and set it on the floor.';
        var arr = [];
        pos = str.indexOf('e');
        while (pos !== -1){
            arr.push(pos);
            pos=str.indexOf('e',pos+1);
        }
        console.log(arr)
    </script>

7.3Date日期對象

7.3.1日期對象的方法

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        var now = new Date();
        console.log("new Date():",now);
        var xmas = new Date('December 25,1998 13:30:00');
        console.log("new Date('December 25,1998 13:30:00'):",xmas);
        console.log("new Date(1998,11,25):",new Date(1998,11,25));
        console.log("new Date(1998,11,25,14,23,0):",new Date(1998,11,25,14,23,0));

        console.log("now.getDate():",now.getDate());//獲取日子（1-31）
        console.log("now.getMonth():",now.getMonth());//獲取月份（0-11）
        console.log("now.getFullYear():",now.getFullYear());//獲取年份
        console.log("now.getDay():",now.getDay());//獲取一星期中的第幾天
        console.log("now.getHours():",now.getHours());//獲取小時(shí)(0-23)
        console.log("now.getMinutes():",now.getMinutes());//獲取分鐘(0-59)
        console.log("now.getSeconds():",now.getSeconds());//獲取秒(0-59)

        console.log("now.toDateString():",now.toDateString());//星期 月 日 年
        console.log("now.toTimeString():",now.toTimeString());//時(shí) 分 秒 時(shí)區(qū)
        console.log("now.toLocaleDateString():",now.toLocaleDateString());
        console.log("now.toLocaleTimeString():",now.toLocaleTimeString());
        console.log("now.toLocaleString():",now.toLocaleString());
        console.log("now.toUTCString():",now.toUTCString());

    </script>
</head>

<body>
</body>
</html>

7.3.2日期對象小應(yīng)用

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        //6:27:35 P.M
        //6:04:01 A.M
        var now = new Date();
        var hour = now.getHours();//0-23
        var minite = now.getMinutes();//0-59
        var second = now.getSeconds();//0-59
        var temp = ''+hour >12?hour-12:hour;
        if(hour === 0){
            temp = '12';
        }
        temp = temp + (minite < 10? ':0':':')+minite;
        temp = temp + (second < 10? ':0':':')+second;
        temp = temp + (hour >= 12? 'P.M':'A.M.');
        console.log(temp);
    </script>
</head>
<body>
</body>
</html>

7.4編碼和解碼方法

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        var uri = 'http://www.apeland.cn/web/index.html?name=zhangsan';
        encode_uri = encodeURI(uri);
        //encodeURIComponent,decodeURIComponent使用的最多
        //因?yàn)樵摲椒梢跃幋a和解碼的范圍更大
        encode_uri_Component = encodeURIComponent(uri);
        console.log("encodeURI(uri)",encode_uri);
        console.log("encodeURIComponent(uri)",encode_uri_Component);

        console.log("decodeURI(encode_uri)",decodeURI(encode_uri));
        console.log("decodeURI(encode_uri_Component)",decodeURI(encode_uri_Component));
        console.log("decodeURIComponent(encode_uri)",decodeURIComponent(encode_uri));
        console.log("decodeURIComponent(encode_uri_Component)",decodeURIComponent(encode_uri_Component));
    </script>
</head>
<body>
</body>
</html>

7.5window對象

所有變量和方法都屬于window對象。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        var a =3;
        console.log(window.a);
        function hello() {
            alert(window.a);
        }
        window.hello();
    </script>
</head>
<body>
</body>
</html>

7.6math對象

7.6.1math方法試驗(yàn)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        var max = Math.max(3,34,55,21);
        var min = Math.min(3,34,55,21);
        console.log("Math.max(3,34,55,21)",max);
        console.log("Math.min(3,34,55,21)",min);
        var arr = [1,2,45,23,56,34];
        console.log("arr",arr);
        var max = Math.max.apply(null,arr);
        var min = Math.min.apply(null,arr);
        console.log("Math.max.apply(null,arr)",max);
        console.log("Math.min.apply(null,arr)",min);

        var t = 123.12312;
        console.log("Math.floor(123.12312)",Math.floor(123.12312));//向下取整，稱為地板函數(shù)
        console.log("Math.ceil(123.12312)",Math.ceil(123.12312));//向上取整，天花板函數(shù)
        console.log("Math.random(34)",Math.random());//隨機(jī)數(shù)，默認(rèn)0-1之間的隨機(jī)數(shù)
        console.log("Math.round(123.78)",Math.round(123.12312));

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

7.6.2獲取min-max之間的整數(shù)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        //獲取1-100之間的隨機(jī)數(shù)
        function random() {
            return Math.floor(1+Math.random()*(100-1))
        }
        console.log(random())
    </script>
</head>
<body>
</body>
</html>

7.6.3獲取隨機(jī)顏色

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        function random(min,max) {
            return Math.floor(min+Math.random()*(max-min));
        }
        //獲取隨機(jī)顏色 rgb(0-255,0-255,0-255);
        function randomColor() {
            var r = random(0,256),g = random(0,256),b = random(0,256);
            var result = "rgb("+r+","+g+","+b+")";
            //// 模板字符串 ``
            //var result = `rgb(${r},${g},$)`;
            return result;
        }
        var rc = randomColor();
        console.log(rc);

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

7.6.4獲取隨機(jī)驗(yàn)證碼

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        function random(min,max) {
            return Math.floor(min+Math.random()*(max-min));
        }
        //隨機(jī)驗(yàn)證碼
        function random_check_code() {
            var code='';
            var codeLength = 4;
            var randomCode = [0,1,2,3,'a','b','c','d','A','D','E'];
            for(var i=0;i<codeLength;i++){
                var index = random(0,11);
                code += randomCode[index];
            }
            return code;
        }
        console.log(random_check_code());
    </script>
</head>
<body>
</body>
</html>