如何限制非字母字符不是密码的第一个或最后一个字符

Question

如何限制密码，使其不允许第一个或最后一个字符为非字母字符（请参阅“标题”）？

我的HTML代码：

<form action = "." method="post"> 
    <input type="password" 
    placeholder = "New Password..." 
    name= "password" 
    title = "Password must be at least 8 characters, at least one alphabetic character [a-zA-Z], at least one non-alphabetic character, which is not the first or last character." 
    pattern="(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}"> 
</form> 

例如：密码hi123 * HI被接受，但我怎么拒绝*hi123HI由于*是第一个字符（同样的问题，如果*是最后一个字符，或特殊字符或数字既是第一个也是最后一个字符）。

Answer 1

添加否定向前看符号检查最初和最后的字符：

/(?![^A-Z])(?!.*[^A-Z]$)(?=.*[A-Z])(?=.*[^A-Z]).{8,}/i 
^^^^^^^^^^            NO INITIAL SPECIAL CHAR 
      ^^^^^^^^^^^^^         NO FINAL SPECIAL CHAR 
         ^^^^^^^^^^^      AT LEAST ONE LETTER 
            ^^^^^^^^^^^^   AT LEAST ONE SPECIAL CHAR 
               ^^^^^^  EIGHT OR MORE CHARS