title: Screen flickering in opera when scrolling with .animate .scrollTop()
body: <p>Here is the website im working on:
  <a href="http://kognitek.nazwa.pl/stockize/mak/MMprodukcja/parallaxProject/stronaTestowa/test.html" rel="nofollow noreferrer">http://kognitek.nazwa.pl/stockize/mak/MMprodukcja/parallaxProject/stronaTestowa/test.html</a></p>
  <p>The site is flickering while <strong>scrolling down with arrow keys</strong> on opera.
  Here is the code i use for scrolling:</p>
  <pre><code>//bottom of index.html
  else if ($.browser.opera) {
  
      $(function() {
          $('html').on('keydown', function(event) {
              var keypressed = event.keyCode;
              var curScroll = $('html').scrollTop();
              var keys = scrollKeys.length;
              var moved = false;
              console.log(&quot;keypressed: &quot; + keypressed);
              for (i = 0; i &lt; keys; i++) {
                  console.log(&quot;curScroll: &quot; + curScroll)
                  if (moved === false) {
                      if (keypressed === 40 &amp;&amp; i != (keys - 1) &amp;&amp; parseInt(scrollKeys[i]) &lt;= curScroll &amp;&amp; parseInt(scrollKeys[i + 1]) &gt; curScroll) {
                          $('html').animate({
                              scrollTop : (parseInt(scrollKeys[i + 1]))
                          }, 'slow', function() {});
                          console.log('down');
                          moved = true;
                      } else if (keypressed === 38 &amp;&amp; i != 0 &amp;&amp; parseInt(scrollKeys[i]) &gt;= curScroll &amp;&amp; parseInt(scrollKeys[i - 1]) &lt; curScroll) {
                          $('html').animate({
                              scrollTop : (parseInt(scrollKeys[i - 1]))
                          }, 'fast', function(){});
                          console.log('up');
                          moved = true;
                      }
                  }
              }
          });
      });
  
  }
  </code></pre>
  <p>I already spent some time trying to fix this and still cant find a reason for this behavior. Site works fine in Chrome, Firefox, IE8, IE9. Problem occurs only in Opera. I know i got this part of code x3 at the end of my index.html, gonna optimize this as soon as i find solution.</p>
  <p>Any idea whats wrong here?</p>
  <h3>Edit:</h3>
  <p>I created this fiddle: <a href="http://jsfiddle.net/mymlyn/Mr5vR/" rel="nofollow noreferrer">http://jsfiddle.net/mymlyn/Mr5vR/</a> At first, script seems fine, but when you reach the bottom, and try to go up again, screen starts to flicker</p>
  <h3>Edit2:</h3>
  <p>I think its prevent default issue, working this out atm</p>
  <h3>EditX:</h3>
  <p>I wish i didnt fail editing this file so it didnt became a community wiki... anyways i upgraded the code and its available here:
  <a href="http://cssdeck.com/labs/swayiqbq/2" rel="nofollow noreferrer">http://cssdeck.com/labs/swayiqbq/2</a>
  It uses .browser thats gonna be removed from jquery 1.9.</p>