1.学习资料

​​​​​​【优极限】 HTML+CSS+JavaScript+jQuery前端必学教程，小白教学，前端基础全套完成版_哔哩哔哩_bilibili

2.

var arr1=[];
		   console.log(arr1);
		   var arr2=[1,2,'a',true];
		   console.log(arr2);
		   //直接实例化
		   var arr3=new Array(1,2,3);
		   console.log(arr3);
		   //定义数组并设置长度
		   var arr4=new Array(5);
		   console.log(arr4);
		   console.log("==========");
		   //获取指定下标的值
		   console.log(arr2[1]);
		   //如果下标不存在
		   console.log(arr2[10]);
		   //设置指定下标的值
		   arr2[1]=20;
		   console.log(arr2);
		   //如果下标不存在
		   arr2[10]=100;
		   console.log(arr2);

2.1

 console.log(arr3.length);
		   //设置数组的长度
		   arr3.length=5;
		   console.log(arr3);
		   //设置数组的属性
		   arr3.name="zhangsan";
		   console.log(arr3);
		   arr3["pwd"]="123456";
		   console.log(arr3);
		   //获取数组的属性
		   console.log(arr3["name"]);
		   console.log("==========");
		   /*数组的遍历*/
		   console.log(arr3);

 2.2

console.log("---for循环遍历---");
		   //for循环遍历
		   for(var i=0;i<arr3.length;i++) {
		    console.log("索引：" + i + ",值："+arr3[i]);
		   }
		   //for...in
		   console.log("---for...in---");
		   for(var i in arr3) {
		    console.log("下标："+i+",值："+arr3[i]);
		   }
		   //forEach
		   console.log("---forEach---");
		   arr3.forEach(function(element,index) {
		    console.log("下标："+index+",值："+element);
		   });
		   console.log("==========");
		      /*数组提供的方法*/
		      var arr5=["a","b","c"];
		   arr5[arr5.length]="d";
		   arr5.push("e");
		   console.log(arr5.indexOf("a"));
		   console.log(arr5.indexOf("t"));
		   console.log(arr5.join("-"));
		   var str="1,2,3,4,5";
		   console.log(str.split(","));

2.3

 function fn01(a,b) {
		    console.log(a+b);
		   }
		   console.log(fn01);
		   var fn02=function(a,b) {
		    console.log(a+b);
		   }
		   console.log(fn02);
		   var fn03=new Function('a','b','return (a+b);');
		   console.log(fn03);
		   function fn04(a,b) {
		    return (a+b);
		   }

 2.4

 console.log("==========");
		   function test01(x,y) {
		    console.log(x+y);
		   }
		   test01();
		   test01(1);
		   test01(1,2);
		   function test02(x,x) {
		    console.log(x);
		   }
		   test02(1,2);
		   function test03(x) {
		    x=x||"x";
		    console.log(x);
		   }
		   test03(10);
		   test03();
		   function test04(x) {
		    (x==null&&x!=undefined)?x=x:x="x";
		    console.log(x);
		   }
		   test04();
		   test04("Hello");
		   var num=10;
		   function test05(num) {
		    num=20;
		   }
		   test05(num);
		   console.log(num);
		   var obj={name:"zhangsan"};
		   console.log(obj);
		   function test06(o) {
		    o.name="lisi";
		   }
		   test06(obj);
		   console.log(obj);

2.5

console.log("===========");
		   function f1() {
		    console.log("常用调用模式...");
		   }
		   f1();
		   var f2=function(a) {
		    console.log("函数调用模式...");
		    return a;
		   }
		   var num1=f2(1);
		   console.log(num1);
		   var obj={
		    name:"zhangsan",
		    age:18,
		    sex:true,
		    cats:["小红","小李"],
		    dog:{
		     name:"旺旺",
		     age:1
		    },
		    sayHello:function() {
		     console.log("你好");
		    }
		   }
		   console.log(obj);
		   console.log(obj.dog);
		   console.log(obj.sayHello);
		   obj.sayHello();
		   console.log("==========");
		   function a1() {
		    console.log("没有返回值...");
		    return;
		    console.log('..........');
		   }
		   console.log(a1());
		   function a2() {
		    console.log("有返回值...");
		    return "test";
		   }
		   console.log(a2());
		   console.log("==========");
		   var pp="Hello";
		   function qq() {
		    var box=10;
		    box2=20;
		   }
		   qq();
		   console.log(qq);
		   console.log(box);
		   console.log(box2);