function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }
      func();
    }
  }
}

function goToCategory(category, style) {
	document.location.href="index.php?category=" + category + "&style=" + style;
}

function showCategories() {
	 document.all.categories.style.opacity = 1.0;
}

addLoadEvent(function() {
  new Effect.Opacity('categories', {duration:1.0, from:0.0, to:1.0, afterFinish: showCategories});
});