title: CSS position:fixed inside a positioned element
body: <p>I have a positioned div whose content can be too long so scrollbars appear (<code>overflow:auto</code> set). It functions as a dialog box in an ajax app. I want to fix a close button on it's right top corner so when the user scrolls the div it won't scroll away.</p>
  
  <p>I tryed it with <code>position:fixed; right:0; top:0</code> but it placed the button on the right top of the page not in the div (in firefox).</p>
  
  <p>Is it possible to do this button placement using CSS only without hacking with the offsetWidth/Height in js on every scroll event?</p>
  
  <p>ps: the div's height and width is not a fixed value it depends on the content's size and the browser window's size. User can also resize it if he want.</p>