[fix] Invalid regular expression

I'm getting `Invalid regular expression` error I think the `/` should be escaped. 
Instead of `|./?` should be `|.\/?`
```javascript
// current version
op = nickname.replace(/[\s!@#$%^&*()_+=\[{\]};:<>|./?\,\\'""-]/g, '_');
// should be
op = nickname.replace(/[\s!@#$%^&*()_+=\[{\]};:<>|.\/?\,\\'""-]/g, '_');
```