title: How to remove diacritics from text?
body: <p>I am making a swedish website, and swedish letters are å, ä, and ö.</p>
  
  <p>I need to make a string entered by a user to become url-safe with PHP.</p>
  
  <p>Basically, need to convert all characters to underscore, all EXCEPT these:</p>
  
  <pre><code> A-Z, a-z, 1-9
  </code></pre>
  
  <p>and all swedish should be converted like this:</p>
  
  <p>'å' to 'a' and 'ä' to 'a' and 'ö' to 'o' (just remove the dots above).</p>
  
  <p>The rest should become underscores as I said.</p>
  
  <p>Im not good at regular expressions so I would appreciate the help guys!</p>
  
  <p>Thanks</p>
  
  <p>NOTE: NOT URLENCODE...I need to store it in a database... etc etc, urlencode wont work for me.</p>