1.自定义对象的定义和使用

//1.使用原始的方式创建对象var obj = new Object();obj.name = \"zhangsan\"; //为obj对象添加属性obj.age = 20;obj.say = function(){ //添加功能（函数/方法）console.log(this.name,\":\",this.age);}//测试console.log(obj.name);console.log(obj.age);obj.say()//2.使用工厂模式创建对象function createObject(name,age){var obj = new Object();obj.name = name; //为obj对象添加属性obj.age = age;obj.say = function(){ //添加功能（函数/方法）console.log(this.name,\":\",this.age);}return obj;}//测试var ob1 = createObject(\"lisi\",20);console.log(ob1.name);ob1.say();var ob2 = createObject(\"wangwu\",25);console.log(ob2.name);ob2.say();//3.使用自定义构造函数创建对象function Stu(name,age){this.name = name;this.age = age;this.say = function(){console.log(this.name,\":\",this.age);}}//测试var s1 = new Stu(\"zhaoliu\",28);var s2 = new Stu(\"xiaoli\",21);s1.say()s2.say()//4.直接创建自定义对象//4.1var obj={};obj.name=\"小白\";obj.say=function () {console.log(\"我叫: \"+this.name);};obj.say();//4.2最常用var obj2={name:\"小明\",age:20,say:function () {console.log(\"我叫: \"+this.name+\"; 年龄: \"+this.age);},};obj2.say();//对象.constructor查看当前对象的构造函数是谁var a = [10,20,30];console.log(a.constructor == Array);//推荐数组采用这种方式，因为typeof得到的是object类型console.log(s1 instanceof Stu);

2.JavaScript内置对象

2.1Array数组

//内置对象--Array数组var a1 = new Array(); //定义一个空数组var a2 = new Array(10); //定义一个长度为10数组（值：undefined）var a3 = new Array(10,20,30); //定义一个指定数值的数组console.log(a1.length);console.log(a2.length);console.log(a3.length);var a4 = [10,20,30,40,50]; //快捷定义数组//数组的遍历for(var i=0; i<a4.length;i++){console.log(i,\"=>\",a4[i]);}for(var i=a4.length-1; i>=0;i--){console.log(i,\"=>\",a4[i]);}//只能正序for(var i in a4){console.log(i,\"=>\",a4[i]);}//foreach迭代只能正序，不了解语法？a4.forEach(function(v){console.log(v);});//数组的方法：console.log(a4.toString());//转换成字符串console.log(a4.join(\":\"));//输出时以冒号隔开var aa = [1,2,3];console.log(aa.concat(4,5));//两个数组连接，前数组的尾部加后数组的首部var b = [10,50,30,20,70,40];console.log(b.join(\":\"));console.log(b.sort().join(\":\"));//从小到大排序console.log(b.reverse().join(\":\"));//反转数组var aa = new Array(10,20,30);console.log(aa.join(\":\"));aa.push(50);//尾部添加数据aa.push(40);console.log(aa.join(\":\"));aa.pop();//尾部删除数据console.log(aa.join(\":\"));//清空console.log(b.join(\":\"));b.length = 3;//强制只留下数组前3个数据console.log(b.join(\":\"));b = [];//强制清空数组console.log(b.join(\":\"));

2.2基本包装类型

//内置对象--基本包装类型        var s1 = \'zhangsan\';        console.log(s1.substring(2,5))        //等价于        var s2 = new String(\"zhangsan\");        console.log(s2.substring(2,5));var num = 20.5678;        //等价于        var num = Number(20.5678);//强转        var num = new Number(20.5678);//创建Number对象        console.log(num.toFixed(2));//将数字转换为字符串，传入小数点应保留几位的参数//布尔值包装类对象        //toString()  把逻辑值转换为字符串并返回结果        //valueOf()   返回布尔对象的原始值        var boo = new Boolean(true);        document.write(boo.toString());        <br/>        var boo1 = new Boolean(false);        document.write(boo1.valueOf());

2.3Date日期

//获取当前日期的函数方法    function formatDate(dd){        if(!dd instanceof Date){            return;        }        var y = dd.getFullYear(),            m = dd.getMonth()+1,            d = dd.getDate(),            hh = dd.getHours(),            mm = dd.getMinutes(),            ss = dd.getSeconds();        //判断单位数字前补零操作        hh = hh<10?\'0\'+hh:hh;        mm = mm<10?\'0\'+mm:mm;        ss = ss<10?\'0\'+ss:ss;        return y+\"-\"+m+\"-\"+d+\" \"+hh+\":\"+mm+\":\"+ss;    }    var dd = new Date();    //从1970年1月1日零时零分0秒至今的毫秒数    document.write(\"时间戳：\"+dd.valueOf());document.write(\"<h2>\"+formatDate(dd)+\"</h2>\");

2.3String字符串

var s1 = \"ZhangSanFeng\";    document.write(s1+\"<br/>\");    document.write(s1[5]+\"<br/>\");//获取第5个位置的字符    document.write(s1.charAt(5)+\"<br/>\");//获取第5个位置的字符    document.write(s1.substr(5,3)+\"<br/>\");//截取从索引5开始后3个    document.write(s1.substring(5,8)+\"<br/>\");//截取5.6.7三个索引位置的字符    document.write(\"小写：\"+s1.toLowerCase()+\"<br/>\");    document.write(\"大写：\"+s1.toUpperCase()+\"<br/>\");    //子串查找    document.write(s1.indexOf(\"an\")+\"<br/>\");//从前往后查找    document.write(s1.lastIndexOf(\"an\")+\"<br/>\");//从后往前查找    //替换    document.write(s1.replace(\"SanFeng\",\"WuJi\")+\"<br/>\");//逗号全部替换    document.write(\"10,20,30,40\".replace(/,/g,\":\")+\"<br/>\");var str = \"10:23:45:67:87:65\";    console.log(str);    console.log(str.split(\":\"));//根据冒号的分割组成数组Arrayvar s2 = \" zhangsan \";    console.log(\"#\"+s2+\"#\");    console.log(\"#\"+s2.trim()+\"#\");//去除空格字符

2.4Math对象

console.log(Math.abs(-20));    console.log(Math.ceil(10.000000001)); //进一取整    console.log(Math.floor(10.9999999)); //舍去取整    console.log(Math.round(10.5)); //四舍五入取整    console.log(Math.max(10,20)); //最大    console.log(Math.min(10,20)); //最小console.log(Math.random()) //0~1的随机数    console.log(Math.ceil(Math.random()*1000000)%10+1) //1~10的随机数