1,密码6-8位只能包含数字大小写字母: /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])[A-Za-z0-9]{6,8}$/;
2,由右向左每3位数字加一个逗号隔开:/(?=(?!\b)(\d{3})+$)/g; '12345678'.replace(reg,','); = 12,345,678
3,检测html标签:/^<(\w+)\/?>(?:<\/\1>|)$/ eg: <div></div> <img/>
4, 匹配id或标签或class选择器:/^(?:#([\w-]+)|(\w+)|.([\w-]+))$/ eg: #id .class p