title: Why this is executed twice?
body: <p>I have code like this:</p>
  
  <pre><code>$(document).ready(function() {
  
      $("div #covert, div #coverb").height($(window).height() / 2 + 1);
      $(window).resize(function() {
          $("div #covert, div #coverb").height($(window).height() / 2 + 1);
          covconcr();
      });
  
      function covconcr() {
          $('div #covercon').css('left', $(window).width() / 2 - $('#covercon').width() / 2);
      }
  
      covconcr();
  
      function hidecover() {
          var goup = $('div #covert').height();
      }
  
      $("div #covercon").fadeOut("fast").fadeIn("fast").fadeOut("fast").fadeIn("fast").fadeOut("fast").fadeIn("fast").fadeOut("fast").fadeIn("fast").fadeOut("fast").delay(100).fadeIn("fast", function() {
          $(this).stop();
      });
  
      $('title').html('Drink86_browser.detection');
  
      var logoop;
  
      jQuery.each(jQuery.browser, function() {
          if ($.browser.msie) {
              $('div #covercon').delay(3000, function() {
                  $(this).html("YOUR BROWSER IS: INTERNET EXPLORER.");
                  $('title').html('Drink86_your.browser.is.internet.explorer');
              });
          }
          else if (!$.browser.msie) {
              function update() {
                  //$('#site').load('site.php');
                  $('div #covercon').html("YOUR BROWSER IS: " + jQuery.uaMatch(navigator.userAgent).browser + ".");
                  covconcr();
                  $('title').html('Drink86_your.browser.is.' + jQuery.uaMatch(navigator.userAgent).browser + ' ');
  
                  function hidecov() {
                      $('title').html('Drink86_loading_files');
                      $('#covercon').html($('#loading').html());
                      covconcr();
                      var timer = setInterval(function() {
                          $("#loadingpro").html(Math.round($("#progress").width() / 4) + "%");
                      }, 20);
                      $("#progress").animate({
                          width: 400
                      }, 2000, function() {
                          $('title').html('Drink86_');
                          clearInterval(timer);
                          $('#covercon').delay(700).fadeOut('fast', function() {
                              //    if(logoop!="yes"){
                              $('#logobig').css('left', $(window).width() / 2 - $('#logobig').width() / 2).css('top', $(window).height() / 2 - $('#logobig').height() / 2);
                              $('#logobig').fadeIn(3000).delay(2500).fadeOut(3000);
                              logoop = "yes";
                              // }
                          });
                      });
                  }
                  setTimeout(hidecov, 1000);
              }
              setTimeout(update, 3100);
          }
      });
  });
  </code></pre>
  
  <p>operation with <code>#logobig</code> (<code>fadeIn</code> and <code>fadeOut</code>) is executed twice.
  why?
  i had previous issues similiar to those but then they were executed twice just in Firefox.
  any ideas why?</p>