JS内置对象-String对象、Date日期对象、Array数组对象、Math对象
2017-07-28 22:52
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一、JavaScript中的所有事物都是对象:字符串、数组、数值、函数...
1、每个对象带有属性和方法
JavaScript允许自定义对象2、自定义对象
a、定义并创建对象实例![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/de174f128c69f097ed97b746adab0c8d.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/2b7a3926f812472f867abfab4e451bc5.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/75b3c0d07221837925e28cabeb328040.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/c0b3bb3e853ac220dbb242ba4502becb.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/325ccc7fddac50cd34df02a47d32e0cc.png)
b、使用函数来定义对象,然后创建新的对象实例
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/d95944bc6f5555b76b0a281ac4da2398.png)
二、JS内置对象-String
1、string对象
string对象用于处理已有的字符串字符串可以使用单引号或者双引号
2、indexOf( ) 在字符串中查找字符串,如果匹配成功返回首字母所在的位置,否则返回-1
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/c4b29609a3332e2dd2cb153940a2b54e.png)
3、match() 匹配成功,返回匹配成功的数组,否则就返回null
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/4c0b0c2b0a742075037bf672869680f6.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/8b257ba643e705752facda4aa6903f61.png)
4、replace str.replace(查找的字符,新的字符串)匹配成功,用新的字符去替换匹配成功的字符
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/0dc1e235dc2b88d9e9579b00827ad943.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/afb74f4e58db6f4168c0ef9ec1f374ce.png)
5、toUpperCase( )转换为大写
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/63fa2e814b5d502373232b82321af328.png)
常见的属性和方法如下:
属性:length、prototype、constructor方法:charAt( )、charCodeAt( )、concat()、indexOf()、match()、replace()、search()、slice()、substring()、substr()、valueOf()、toLowerCase()、toUpperCase()、split()
三、JS内置对象-Date日期
1、Date对象
日期对象用于处理日期和时间2、获得当日的日期
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/71194cd6f966b0465b0a9f0f5526d959.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/724f33a2b8df73847c85d0b1b33f992b.png)
3、常用的方法:
获取年份:getFullYear()![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/a44dde60fcad055659f4365985879fd5.png)
获取月份:getMonth()+1
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/774a2f5e0b7cf7f6d5b612e0805d55b3.png)
获取日期:getDate()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/52f6cbc6896b72e05e8002d83d6e4445.png)
获取星期:getDay()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/74bb6cc4ecb9d1f58018f9f191510db2.png)
获取小时:getHour()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/8bfab6812fadfd108754b7704591f6b7.png)
获取分钟:getMinutes()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/3ae8e7754980a200fe990a66cee50fcf.png)
获取秒:getSeconds()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/8fa39d6a847edb2448bb0f992a874308.png)
获取毫秒:getTime()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/9f66b9de49e65fa6c038f5d88379f010.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/d5521ed46aac7fb27f2c1c1e08b20213.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/414dad9abf04fc2fca03ebe361d27068.png)
四、JS内置对象-Array
1、Array对象
使用单独的变量名来存储一系列的值2、数组的创建
eg:var myarr = ["hello","world","hi"]3、数组的访问
通过指定数组名以及索引号,可以访问某个特定的元素注意:[0] 是数组的第一个元素。[1] 是数组的第二个元素
4、数组常用的方法:
concat()合并数组![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/60f737382332707a6f3144bf105b47bf.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/ffe1d2629a0d6ab5ea6802d32a08ca8f.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/361c589ff66fd29cbcb92e27a224d01a.png)
sort() 排序
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/08fad8468c7f8070ae6d2ff006f4aa08.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/00bb36a69fe1ba67508d5cfac239a20d.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/df7b683e32a729dbdbbd96db10c41000.png)
push()末尾追加元素,返回长度
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/ea7378fc262111530835e948e2f4dc26.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/f9ba1007f06d8392ff80e3b7ed701a70.png)
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/01ad0937336091be37c9cabb0dff05c2.png)
reverse() 数组元素翻转
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/9e8a493934bbf64ea62c3102c8255f18.png)
五、JS内置对象-Math
1、Math对象
执行常见的算数任务2、常用的方法:
四舍五入:round()![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/d6d0b403b2e810420c245798c8a07476.png)
返回0~1之间的随机数:random()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/22c87a0dfbdae4f3c85b6ce2eeb781b9.png)
返回最高值:max()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/3b6959554c9b286dcea5fbf726ad6280.png)
返回最低值:min()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/ea5cc1b955dc337baf4397fc1baa479a.png)
返回绝对值:abs()
![](https://oscdn.geek-share.com/Uploads/Images/Content/201707/e963553805df13e19fbdf592cbcda3f5.png)
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