A deep dive into the capabilities and features of JavaScript's built-in objects

In-depth analysis of the functions and characteristics of JS built-in objects

JavaScript is an object-based programming language. It provides many built-in objects, which have various rich features. functions and features. In this article, we will provide an in-depth analysis of some commonly used built-in objects and give corresponding code examples.

1. Math object
   Math object provides some basic mathematical operation methods, such as exponentiation, square root, logarithm, etc. The following are some commonly used Math object method examples:

// 求绝对值
Math.abs(-10);  // 输出：10

// 向上取整
Math.ceil(3.14);  // 输出：4

// 向下取整
Math.floor(3.14);  // 输出：3

// 求最大值
Math.max(1, 2, 3);  // 输出：3

// 求最小值
Math.min(1, 2, 3);  // 输出：1

// 生成一个0到1之间的随机数
Math.random();  // 输出：0.20793662077218673

2. String object
   String object represents a string of characters and provides a series of string processing methods. The following are some commonly used String object method examples:

// 字符串长度
var str = "Hello World";
str.length;  // 输出：11

// 查找子串
str.indexOf("World");  // 输出：6

// 截取子串
str.slice(0, 5);  // 输出：Hello

// 替换子串
str.replace("World", "JavaScript");  // 输出：Hello JavaScript

// 字符串转换为大写
str.toUpperCase();  // 输出：HELLO WORLD

3. Array object
   The Array object is a container used to store a set of data and provides a series of array operation methods. The following are some commonly used Array object method examples:

// 创建一个新数组
var arr = new Array(1, 2, 3);

// 获取数组长度
arr.length;  // 输出：3

// 插入元素
arr.push(4);  // [1, 2, 3, 4]

// 删除并返回最后一个元素
arr.pop();  // 输出：4

// 循环遍历数组
for (var i = 0; i < arr.length; i++) {
   console.log(arr[i]);
}

// 数组元素排序
arr.sort();  // [1, 2, 3]

4. Date object
   Date object is used to represent date and time, and provides some date and time processing methods. The following are some commonly used Date object method examples:

// 获取当前日期和时间
var now = new Date();
console.log(now);  // 输出：Sat Dec 18 2021 14:16:38 GMT+0800 (中国标准时间)

// 获取年份
now.getFullYear();  // 输出：2021

// 获取月份（0表示1月，11表示12月）
now.getMonth();  // 输出：11

// 获取日期
now.getDate();  // 输出：18

// 获取小时
now.getHours();  // 输出：14

// 获取分钟
now.getMinutes();  // 输出：16

Through an in-depth analysis of the built-in objects in JavaScript, we can understand the rich functions and features they provide, and be able to use them more flexibly. to deal with various issues. I hope this article helps you understand JavaScript built-in objects!

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