const test = new RegExp('hello world', 'ig');
console.log(test.test('hello world')); // true

const test = new RegExp('hello world', 'ig');
console.log(test.exec('hello')); // null

const pattern=/Box/ig;
const str="This is a Box! The is a box!";
console.log(str.match(pattern));

const pattern=/Box/i;	//
const str="This is a Box! The is a box!";
console.log(str.search(pattern)); // 10

const pattern=/Box/ig;
const str="This is a Box! The is a box!";
console.log(str.replace(pattern,'Tom'));

const pattern = / /ig;	//空格
const str = "This is a Box! The is a box!";
console.log(str.split(pattern)); //以空格进行分割，返回的是数组
// 输出结果
// [ 'This', 'is', 'a', 'Box!', 'The', 'is', 'a', 'box!' ]

const pattern=/^[a-z]oogle\d$/;
const str="aoogle2";
console.log(pattern.test(str)); // true

const pattern=/baidu|google|bing/; //匹配或选择其中某个字符，不是相等，包含的意思
const str = "baidu a google"; 
console.log(pattern.test(str)); //返回true

const pattern = /^[1-9]{1}[0-9]{5}$/;
const str = "122534"; //共6位数，第一位不能为0
console.log(pattern.test(str)); // true

const pattern = /^[\w]+\.(zip|gz|rar)$/; 
const str="a12_.zip"; //文件名 字母_数字.zip,gz,rar
console.log(pattern.test(str)); // true

 var pattern=/^\s+/; 
 var str=" google ";
 var result=str.replace(pattern,'');
 pattern=/\s+$/;
 result=result.replace(pattern,'');
 

var pattern=/^\s+(.+" google ";
 var result=pattern.exec(str,'')[1];

 console.log('|'+result+'|');

var pattern=/^\s+(.+" google ";
 var result=str.replace(pattern,'$1'); //使用分组模式

 console.log('|'+result+'|'); // |google|

var pattern=/^([\w\.\_]+)@([\w\_]+)\.([a-zA-Z]){2,4}$/;
var str="qzfweb@gmail.com";
console.log(pattern.test(str)); // true