正则表达式字母数字字符-允许连字符和下划线

Question

I need a Regular Expression for Javascript that checks if a password is correct only when 我需要一个Java正则表达式，仅在以下情况下才检查密码是否正确：

Examples: 例子：

I tried using 我尝试使用

var Reg = /^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z-_]{4,12}$/;

It works in PHP, but not in Javascript, any suggestions? 它可以在PHP中运行，但不能在Javascript中运行，有什么建议吗？

Answer 1

Put the hyphen at the end of the character class: 将连字符放在字符类的末尾：

var Reg = /^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z_-]{4,20}$/;

You can also shorten that character class: 您也可以缩短该字符类：

var Reg = /^(?=.*\d)(?=.*[A-Za-z])[\w-]{4,20}$/;

Also, you said 20 characters, not 12. Right? 另外，您说的是20个字符，而不是12个。