title: Why url encode, or which characters to encode
body: <p><a href="http://www.w3schools.com/tags/ref_urlencode.asp" rel="noreferrer">http://www.w3schools.com/tags/ref_urlencode.asp</a></p>
  
  <blockquote>
    <p>Since URLs often contain characters outside the ASCII set, the URL has
    to be converted into a valid ASCII format.</p>
  </blockquote>
  
  <p>But both space, /, % are part of the ASCII character set, so why encode them in the first place? What characters should be encoded?</p>