title: Allowing any character in the URL in CodeIgniter
body: <p>I'm using the CodeIgniter PHP framework. I use JS to dynamically load a PHP page:</p>
  
  <pre><code>$('someIFrame').writeAttribute(
     'src',
     '/index.php/controller/method/' +
     escape(userGeneratedString)
  );
  </code></pre>
  
  <p>When I ran this, CodeIgniter gave me this error:</p>
  
  <pre><code>http://192.168.0.81/index.php/controller/method/dude%27s%20face
  An Error Was Encountered
  The URI you submitted has disallowed characters.
  </code></pre>
  
  <p>This is totally untrue because the URL in question did not contain any disallowed characters. My config file allows all the characters present in that URL:</p>
  
  <pre><code>$config['permitted_uri_chars'] = 'a-z 0-9~%.:_()@\-';
  </code></pre>
  
  <p>So I got frustrated and just allowed all characters to prevent the error.</p>
  
  <pre><code>// Leave blank to allow all characters -- but only if you are insane.
  // DO NOT CHANGE THIS UNLESS YOU FULLY UNDERSTAND THE REPERCUSSIONS!!
  //$config['permitted_uri_chars'] = 'a-z 0-9~%.:_()@\-';
  $config['permitted_uri_chars'] = '';
  </code></pre>
  
  <p>The warning message above this line sounds scary. What can possibly go wrong by allowing all characters? Will I get hacked? </p>