title: What is "i" in "function(i)" in the following JavaScript?
body: <p>In the following code there is "function(i)", but "i" hasn't been declared anywhere previous to this statement.</p>
  
  <pre><code>ul.css({width: 10, overflow: 'visible'}).retarder(100, function(i){
     i.css('visibility',  'visible').animate(
        {width: ul[0].wid,left:-50},
        {duration: 500, complete : function(){
           ul.css('overflow',  'visible');
        }}
     );
  });
  </code></pre>
  
  <p>It looks like it could be similar to a c++ "this" statement.  Is that correct at all?</p>