var overPostfix = '_o';
var selectedPostfix = '_s';
var selectedItemPostfix = '';
var selectedImageName = '';
var preloadFlag = false;

function overOn(_name)
{
	if (document.images && (preloadFlag == true) && (document[_name] != null))
	{
	  iPath = document[_name].src;
	  pointPos = iPath.lastIndexOf('.');
	  imgName = iPath.substring(0,pointPos);
	  postfixPos = imgName.lastIndexOf(selectedPostfix);
	  if (postfixPos == (imgName.length - selectedPostfix.length))
	  {
	    selectedItemPostfix = imgName.substring(postfixPos,imgName.length);
	    imgName = imgName.substring(0,postfixPos);
	  }
	  imgExt = iPath.substring(pointPos,iPath.length);
	  document[_name].src = imgName+overPostfix+imgExt;
	  selectedImageName = _name;
	}
}

function overOff()
{
	if (document.images && (preloadFlag == true) && (document[selectedImageName] != null))
	{
	  iPath = document[selectedImageName].src;
	  pointPos = iPath.lastIndexOf('.');
	  imgName = iPath.substring(0,pointPos);
	  postfixPos = imgName.lastIndexOf(overPostfix);
	  if (postfixPos != -1)
	    imgName = imgName.substring(0,postfixPos);
	  imgExt = iPath.substring(pointPos,iPath.length);
	  document[selectedImageName].src = imgName+selectedItemPostfix+imgExt;
	  selectedItemPostfix = '';
	  selectedImageName = '';
	}
}

function newImage(arg)
{
	if (document.images)
	{
	  rslt = new Image();
	  rslt.src = arg;
	  return rslt;
	}
}