I have a front-end registration page and need to change the validation to add (minimum characters for information on the page and to make fields to accept only letters and other to accept only number how can I accomplish this ) if there is any guide or step by step it will be nice , thanks in advance my site is on this link : todo.net registration page is : todo.net/register
2 Answers
You could use Regex (Regular Expression), /^[a-zA-Z]{3,}$/
would for instance allow a minimum of 3 characters behind the comma would be the max value.
As for numbers it would be something like this /^[0-9]{3,}$/
http://regexr.com/ to test your regex en examples
And I would do this before the user is saved with the users.onBeforeSaveUser
Event in a plugin.
The MN Match Input plugin is a fieldtype for fields that match a regular expression. It sound to me as if it will do what you want.