title: input checkbox true or checked or yes
body: <p>I've seen the three implementations of pre-selecting a checkbox.  I started off using checked="checked" because I thought it was the "proper" way (never did like the "checked"="yes" however).  I am thinking of changing to checked="true" as it seems more readable and is easier to code the JavaScript.  Note that this same question applies to other attributes such as "disabled"="disabled" versus "disabled"="true".  As long as I am consistent, is using "true" the preferred approach?  Thank you</p>
  
  <pre><code>&lt;input type="checkbox" checked="checked" value="123" name="howdy" /&gt;
  &lt;input type="checkbox" checked="true"    value="123" name="howdy" /&gt;
  &lt;input type="checkbox" checked="yes"     value="123" name="howdy" /&gt;
  </code></pre>