function secTab(n)
{
switch(n) {
	case 1:
  		tab1.background="images/menu_on_en.gif";
		break;
	case 2:
  		tab2.background="images/menu_on_en.gif";
		break;
	case 3:
  		tab3.background="images/menu_on_en.gif";
		break;
	case 4:
  		tab4.background="images/menu_on_en.gif";
		break;
	case 5:
  		tab5.background="images/menu_on_en.gif";
		break;
	}
}