<script>
//1.Date对象var d1 = new Date();
//Thu May 02 2019 14:27:19 GMT+0800 (中国标准时间)
         console.log(d1);
//转成2019/5/2 下午2:27:19
        console.log(d1.toLocaleString());//距离1900年经过年数console.log(d1.getYear());//119
//获取当前纪年console.log(d1.getFullYear());//2019
//获取一年中当前月份console.log(d1.getMonth()); //4,   0-11//获取一个月中的日期
        console.log(d1.getDate());//时
        console.log(d1.getHours());
//分
        console.log(d1.getMinutes());
//秒
        console.log(d1.getSeconds());//设置月份时，记得值为0-11var d2 = new Date(2012,11,12,12,12,12);console.log(d2.toLocaleString());//2012/12/12 下午12:12:12//可以创建一个距离1970年经过的毫秒数var d3 = new Date(1528980372222);console.log(d3.toLocaleString())
</script>

<script >console.log(Math.random()) // [0,1) 随机数console.log(Math.abs(-5))  //求取绝对值
console.log(Math.round(4.5)); //四舍五入
console.log(Math.ceil(3.1));  //天花板
console.log(Math.floor(3.9)); //地板
console.log(Math.pow(2,20)); //x的y次幂
console.log(Math.PI); //圆周率
</script>

<script type="application/javascript">//var str = new String("aabbcc");var str2 = "aabdcbc";//console.log(str);
        console.log(str2);//转化大小写console.log(str2.toUpperCase()); //大写console.log(str2.toLowerCase()); //小写//返回指定索引处的字母console.log(str2.charAt(3));//返回指定字母首次出现的索引console.log(str2.indexOf("b"));//返回指定字母最后一次出现的索引console.log(str2.lastIndexOf("b"));//截取子字符串，从x位置截取y个字符console.log(str2.substr(2,3));//截取子字符串，从x位置截到y位置console.log(str2.substring(2,3));//字符串length属性表示字符的个数
        console.log(str2.length)</script>

<script type="application/javascript">//1.在js中，我们可以使用Object对象来表述一个人var obj = new Object();//2.在js中，对象有个特点：属性可以动态的添加//添加属性obj.name = "laowang";//修改属性的值obj.name = "laoma";//删除属性delete obj.name;function factory(name,age){var obj = new Object();obj.name = name;obj.age = age;return obj;}var per1 = factory("laowang",30);console.log(per1.name);var c1 = factory("benz",3);console.log(c1.name);//封装的人“类”function Person(name,age){this.name = name;this.age = age;}var p1 = new Person("zhangsan",20);console.log(p1.name);console.log(p1.age);var p2 = new Person("乔峰",25);console.log(p2.name);console.log(p2.age);p2.skill = "降龙十八掌";console.log(p1.skill);console.log(p2.skill);//为所有对象都添加属性Person.prototype.money = 8888;Person.prototype.like = ["吃饭","睡觉","打豆豆"];Person.prototype.eat = function(){alert("吃饭了，好开心！");}console.log(p1.money);console.log(p2.money);p1.like.push("写Java");console.log(p1.like);console.log(p2.like);p1.money = 88888;console.log(p1.money);console.log(p2.money);function Student(){this.sno = Math.random();}Student.prototype = new Person("lisi",8);var s1 = new Student();console.log(s1.name);console.log(s1.age);console.log(s1.sno);console.log(s1.money);console.log(s1.like)</script>