title: Span attribute on colgroup and col
body: <p>Are these codes logically equivalent?</p>
  
  <pre><code>&lt;colgroup span="7"&gt;
  &lt;/colgroup&gt;
  </code></pre>
  
  <p>And</p>
  
  <pre><code>&lt;col span="7" /&gt;
  </code></pre>
  
  <p>And</p>
  
  <pre><code>&lt;colgroup&gt;
  &lt;col /&gt;
  &lt;col /&gt;
  &lt;col /&gt;
  &lt;col /&gt;
  &lt;col /&gt;
  &lt;col /&gt;
  &lt;col /&gt;
  &lt;/colgroup&gt;
  </code></pre>
  
  <p>Will any attributes via HTML or properties via CSS have equal effect? Can sombody also add "colgroup" Tag. No enough rep for me to do that.</p>