title: JQuery - Input tag change visibility attribute
body: <p>I have a very simple input tag:</p>
  
  <pre><code>&lt;input id="DAhour" type="number" style="width:50px; font-size: xx-small; visibility:hidden"&gt;
  </code></pre>
  
  <p>which at first has to be not visible. Then if I change a combobox to the correct index it should become visible. I managed to get the combobox and the selected item correctly but I cannot make the input tag visible. I tried with:</p>
  
  <pre><code>$("#DAhour").css("visibility", "visible");
  </code></pre>
  
  <p>but it doesn't work because if I check the visibility with</p>
  
  <pre><code>$("#DAhour").is(":visible")
  </code></pre>
  
  <p>it stays always equal to false. Then, when the combobox changes again I should be able to make it not visible again, si I tried again with</p>
  
  <pre><code>$("#DAhour").css("visibility", "hidden");
  </code></pre>