//----------------------------------------------------------------------------
// Check if the fileName have extension ".gif", ".jpg" or ".png".
// return true - if fileName is not set or if extension is valid
// otherwise - false
//----------------------------------------------------------------------------

function isPicture(fileName) 
{
  if(fileName=="")
    return true;
  
  var ext = fileName.substring(fileName.lastIndexOf(".")).toLowerCase();
  
  if(ext==".gif" || ext==".jpg" || ext==".png")
    return true;

  return false;
}

function isVideo(fileName) 
{
  if(fileName=="")
    return true;
  
  var ext = fileName.substring(fileName.lastIndexOf(".")).toLowerCase();
  
//  if(ext==".avi" || ext==".wmv" || ext==".mpg" || ext==".mpeg")
  if(ext==".avi")
    return true;

  return false;
}