javascript正则表达式警告无效的用户名

Question

these are the conditions for a valid username

1. must contain az or AZ
2. can contain 0-9 anywhere
3. must not allow any other characters

so a0 and 0a are valid user names just like username and UserName . i need a regex for this.

the issue optionally allowing 0-9

UPDATE the problem with regex like /\\w+/i is it allows username like 000 but in my case it must contain an alphabet and not any special characters

Answer 1

You don't know how to compose lookahead ? just use

var isValid = /[a-zA-Z]/.test(username) && /^[a-zA-Z\d]$/.test(username);
              ^^^^^^^^^ at last one char
                                           ^^^^^^^^^^^^^only char & digits

You want to learn lookahead ? Just use:

var isValid = /^(?=.*[a-z])[a-z\d]+$/gmi.test(username);

Answer 2

也许是这样的：

/^[a-zA-z0-9]*[a-zA-z][a-zA-z0-9]*$/

Answer 3

简单的解决方案：

/^(\d*[a-zA-Z]+\d*)+$/

Answer 4

the working regex is /^([0-9]+[a-zA-Z]|[a-zA-Z]+[0-9]|[a-zA-Z])+$/ .

it does match 0a a0 aaa

but will not match 000 or +a or a+

please read the question completely, before putting down votes