1.匹配11位手机号，开头字母位1
^1d{10}$
2.匹配姓名，中文3-6位
[u4e00-u9fa5]{3,6}
3.匹配密码，必须是6-16位的字符，只能包含数字、字母、下划线：
$w{6-16}^
4.匹配邮箱
^w+@w+(.w+){1,2}
5.匹配座机号
^d{1,3}-d{4,8}$
6.匹配一个正数
^d+(.d+)?$
7.匹配一个小数
^-?d+.d+
8.匹配一个整数
^-?d+$
9.写一个正则表达式，去匹配一个字符串，得到匹配的次数，和匹配的结果
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
var reg = /d{3}/g;
var s = "1234a;sdfja;sd234lkfjasldkfj";
var n = 0;
while(result = reg.exec(s)){
n++;
console.log(result[0]);
}
console.log(`匹配${n}次`);
</script>
</body>
</html>
10.得到一个字符串中中文字符的数量：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
var reg = /[u4e00-u9fa5]/g;
var s = "1234a;s水电费234lkfjasldkfj";
var n = 0;
while(reg.test(s)){
n++;
}
console.log(n);
</script>
</body>
</html>
11.过滤敏感词，将一个字符串中出现的敏感词替换为3个星号：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
var senWords = ["小明", "小红", "小王"];
//将字符串中敏感词汇替换为指定的字符串
function filterSensitiveWords(s, repStr){
var reg = new RegExp(`(${senWords.join("|")})+`,"g");
return s.replace(reg, repStr);
}
console.log(filterSensitiveWords("小明小红小王三个人去上学，课堂上小明调皮捣蛋，小红认真听课，小王在发呆", "***"));
</script>
</body>
</html>
12.将一串数字从后向前每三个数字用逗号隔开：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
var s = "123123123";
//不是字符边界，后面是三个数字出现1到多次直到结束，全局匹配
var reg = /B(?=(d{3})+$)/g;
console.log(s.replace(reg, ","));
</script>
</body>
</html>
结果展示：
13.判断密码强度，要求密码中必须出现小写字母、大写字母、数字、特殊字符(!@#_,.)：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<script>
//判断密码强度，要求密码中必须出现小写字母、大写字母、数字、特殊字符(!@#_,.)
var s = "123asdf&AAA(";
var reg = /^(?=.*[a-z])(?=.*[A-Z])(?=.*d)(?=.*[(!#_,.)]).{6,12}$/;
console.log(reg.test(s));
</script>
</body>
</html>