Answers.Body: <p>You could use Regex (Regular Expression), <code>/^[a-zA-Z]{3,}$/</code> would for instance allow a minimum of 3 characters behind the comma would be the max value.</p>
  
  <p>As for numbers it would be something like this <code>/^[0-9]{3,}$/</code></p>
  
  <p><a href="http://regexr.com/" rel="nofollow">http://regexr.com/</a> to test your regex en examples</p>
  
  <p>And I would do this before the user is saved with the <code>users.onBeforeSaveUser</code> Event in a plugin.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-10-18T08:29:34.933Z
Answers.LastActivityDate: 2016-10-18T17:59:38.237Z
Answers.LastEditDate: 2016-10-18T17:59:38.237Z
Answers.UserDisplayName: Bram B
Answers.Body: <p>The <a href="https://github.com/marionnewlevant/craft-mn_matchinput" rel="nofollow">MN Match Input</a> plugin is a fieldtype for fields that match a regular expression. It sound to me as if it will do what you want.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2016-10-19T16:11:41.570Z
Answers.LastActivityDate: 2016-10-19T16:11:41.570Z
Answers.UserDisplayName: Marion Newlevant
Body: <p>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 </p>
  
Tags: <registration><validation>
Title: Front-end registration validation
ThreadText: # Front-end registration validation
  
  (Asked by: username_0 on 2016-10-18)
  
  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
  
  **Tags:** registration, validation
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2016-10-18. Score: 3 | Accepted answer
  
  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.
  
  
  ---
  
  ### Answer by username_2 on 2016-10-19. Score: 1
  
  The [MN Match Input](https://github.com/username_2/craft-mn_matchinput) plugin is a fieldtype for fields that match a regular expression. It sound to me as if it will do what you want.
  
  
  ---
  
  