title: RGB transparent color value in Javascript
body: <p>I've got a script that changes some CSS on scroll and it currently uses a hex value for a color. I need to switch the #ffffff to rgba(255, 255, 255, 0.6) I think the .6 messes up the syntax but I don't know how to make it right.</p>
  
  <pre><code>var $mainlogo = jQuery('#mainlogo');
  var $menuback = jQuery('.x-navbar');
  jQuery(document).scroll(function() {
      $mainlogo.css({display: jQuery(this).scrollTop()&gt;170 ? "block":"none"});
  $menuback.css({background: jQuery(this).scrollTop()&gt;170 ? "#ffffff":"none"});
  });
  </code></pre>