title: Forms 3 or 4 Random Password Chars from password PHP
body: <p>I've seen a few sites asking the user to input 3 or 4 chars from their password randomly to gain access on a website account. I would like to know how to do this using PHP5, MySQL and possibly Ajax.</p>
  
  <p>So, if I have a standard login form I'd have</p>
  
  <pre>username:
  password:
  Submit Button</pre>
  
  <p>but I'd like to do the following login form:</p>
  
  <pre>username:
  Password (Inptut the following Chars:) Char 1[] Char 3[] char 7[]
  Submit button</pre>
  
  <p>Chars 1, 3 &amp; 7 are random and depending on length of orginal password.</p>
  
  <p>If you've done a script like this and can shed some light on it or possible a full worknig script I can look at I'd be grateful.</p>