title: HTML5 ambiguous ampersands in URLs
body: <p>The <a href="http://validator.w3.org/" rel="nofollow">W3C Validator</a> is firing up an error about ampersands in some of my URLs. For example:</p>
  
  <pre><code>&lt;link href="min/?f=static/css/reset.css,static/css/main5.css&amp;2" rel="stylesheet"&gt;
  </code></pre>
  
  <p>According to the <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html#syntax-ambiguous-ampersand" rel="nofollow">HTML5 spec</a>, however, the validator is wrong:</p>
  
  <blockquote>
    <p>An ambiguous ampersand is a U+0026 AMPERSAND character (&amp;) that is followed by one or more alphanumeric ASCII characters, <strong>followed by a U+003B SEMICOLON character (;)</strong>, where these characters do not match any of the names given in the named character references section.</p>
  </blockquote>
  
  <p><a href="http://mathiasbynens.be/notes/ambiguous-ampersands" rel="nofollow">This site</a> comes to the same conclusion and states that no validators currently implement the spec correctly.</p>
  
  <p>Is there anything definitive on this?</p>