title: Validating custom tumblr theme
body: <p>I am witing a custom tumblr theme. When I went to validate it using the W3C validator I got a bucket full of errors from the code tumblr inserts into the blog outside of my theme code. So I did troubleshooting 101 and installed their default theme and tried to validate it. I used the Redux theme. When I put it into the validator I get these 3 errors:</p>
  
  <pre><code>Line 2, Column 871: Stray doctype.
  
  ….0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;
  
  
  Error Line 3, Column 67: Stray end tag html.
  
  &lt;html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"&gt;
  
  Error Line 3, Column 67: Cannot recover after last error. Any further errors will be ignored.
  
  &lt;html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"&gt;
  </code></pre>
  
  <p>so my question, how critical is validation? The problem I'm trying to solve is that my custom theme is quite sluggish. I figured step 1 to speed it up would be use valid markup. But that does not seem possible. (Also getting buckets of errors from the FB G+ and TW button code that I have no control over). thanks in advance.</p>