title: .is("visible") & .is(":visible") working differently
body: <p>I am using jquery visible selector to check if a child element is visible or not.But surprisingly .is("visible") &amp; .is(":visible") is showing different result on using it with  css visibility:hidden property.When I am using .is('visible') it is alerting false &amp; on using .is(":visible") is it alerting true. But on changing the css property to display:none, the result is consistent.Here is the code.</p>
  
  <p>HTML</p>
  
  <pre><code>&lt;div id="parentEle"&gt;
      I have hidden span
      &lt;span class="hiddenContent"&gt;
          I am hiddenContent
      &lt;/span&gt;
  &lt;/div&gt;
  &lt;button type="button" onclick="_checkChild()"&gt;Check Child&lt;/button&gt;
  </code></pre>
  
  <p>JS</p>
  
  <pre><code>function _checkChild(){
      var x= false;
      x =$("#parentEle").children(".hiddenContent").is(":visible");
      alert(x);
  }
  </code></pre>
  
  <p>CSS</p>
  
  <pre><code>.hiddenContent{
     visibility:hidden
  }
  </code></pre>
  
  <p><a href="http://jsfiddle.net/hc0gb5kf/" rel="nofollow">jsfiddle</a></p>
  
  <p>Can you please help to understand this discrepancy?Thanks  </p>