/*
 * preloads image
 */
function preloadImage(src){
    var image = new Image();
	image.src = src;
};

/*
 * returns element by it's ID
 */
function $(id){
  return document.getElementById(id);
};


function showAjaxLoader(id){
    $(id).style.visibility = 'visible';
}

function hideAjaxLoader(id){
	$(id).style.visibility = 'hidden';
}