title: Do something when page is scrolling and have some position
body: <p>i have a little problem with page scrolling... 
  I wanna to change some css when i'm scrolling page down and if window have 100px from top position...
  This is my code. Much thx for help.</p>
  
  <pre><code>$(document).ready(function(){
      $(window).scroll(function(){
          if ($(window).scroll(100)){
              $('.ufo').css('right','800px');
          }
      });
  });
  </code></pre>