Js-创建对象、字符串对象、获取日期

对象：

<script>    /*创建对象*/    var zhangSan = new Object();    zhangSan.name = "zhangsan";    zhangSan.age = "25";    zhangSan.height = "160";    var zhangSan = {        name: "zhangsan",        age : "25",        height : "160"    };    function show(person) {        console.log(person.name);        console.log(person.age);        console.log(person.height);        console.log(person['name']);    }    show(zhangSan);</script>

字符串对象：

<script>    /*小写转换成大写*/    var s = "jieruijiaoyu";    alert(s.toUpperCase());    /*大写转换为小写*/    var s1 = "JIERUIJIAOYU";    alert(s1.toLowerCase());    var s2 = prompt("请输入一个小写字母");    alert(s2.toUpperCase());    /*返回在指定位置的字符*/    var s3 = "jieruijiaoyu";    alert(s3.charAt(2));    /*返回第一次出现所选字符的索引值    * 所选的字符    * 查找开始的位置*/    var s4 = "hellohello";    alert(s4.indexOf("o",5));    /*截取字符串    * 截取开始的位置(包含)    * 截取结束的位置(不包含)*/    var s5 = "this is js";    var result = s5.substring(5,7);</script>

date对象：

定时器：setInterval

<script>    setInterval(function () {        var date = new Date();/*获取年份*/        var year = date.getFullYear();        console.log(year);/*月份加1*/        var month = date.getMonth() + 1;        console.log(month); /*获取日期*/        var day = date.getDate();        console.log(day);/*获取小时*/        var hour = date.getHours();        console.log(hour); /*获取分钟*/        var minute = date.getMinutes();        console.log(minute); /*获取秒*/        var second = date.getSeconds();        console.log(second); /*获取毫秒*/        var ms = date.getMilliseconds();        console.log(ms); /*获取星期*/ var week = date.getDay() == 0 ? 7 :  date.getDay();        console.log(week);var s = year + "年" + month + "月" + day + "日" + hour + ":" + minute + ":" + second + "星期" + week;     document.getElementById("time").innerHTML = s;    }, 1000);</script>

数学类：

Math. 方法

<script>    var i = Math.PI;    console.log(i);    var j = Math.random();    console.log(Math.floor(j*11));    var k = 3.8;    console.log(Math.floor(k));/*向下取整*/    console.log(Math.ceil(k));/*向上取整*/    console.log(Math.round(k));/*四舍五入*/    var l = -3;    console.log(Math.abs(l));/*绝对值*/</script>