/** Uses the os_urls array variable to return the correct URL depending on the current OS.
    The 'os_urls' variable has to be defined */
function getCurrentOsUrl() {
    if (navigator.platform.indexOf('Win')!=-1) {
        return os_urls.win
    }   

    if (navigator.platform.indexOf('Mac')!=-1) {
        return os_urls.mac
    }

    if (navigator.platform.indexOf('Linux')!=-1) {
        return os_urls.linux
   }
}

/** Toggles the visibility of an element using BlindsUp or BlindsDown 
 Requires prototype.js and scriptaculous.js to be loaded.
*/
function toggleBlinds(idElement,isHidden) {
  if (isHidden) { 
  	Effect.Center(idElement);
    Effect.Appear(idElement); 
    isHidden = false;
  } else { 
    Effect.Fade(idElement); 
    isHidden = true; 
  }
  return isHidden;
}