// universal for all pages
  // TODO: preload imgs
	DOM = (document.getElementById) ? 1 : 0;
	function hide(ctrl){
		if(DOM && document.getElementById(ctrl)) document.getElementById(ctrl).style.display = 'none';
	}
	function show(ctrl){
		if(DOM && document.getElementById(ctrl)) document.getElementById(ctrl).style.display = 'block';
	}
	function hideAll() {
  	hide('navigation_1_1');
  	hide('navigation_1_2');
  	hide('navigation_1_3');
  	hide('navigation_1_4');
  	hide('navigation_1_5');
  	hide('navigation_1_1_1');
  	hide('navigation_1_1_2');
  	hide('navigation_1_1_3');
  	hide('navigation_1_1_4');
  	hide('navigation_1_1_5');
  	hide('navigation_1_2_1');
  	hide('navigation_1_2_2');
  	hide('navigation_1_2_3');
  	hide('navigation_1_2_4');
  	hide('navigation_1_2_5');
  	hide('navigation_1_3_1');
  	hide('navigation_1_3_2');
  	hide('navigation_1_3_3');
  	hide('navigation_1_3_4');
  	hide('navigation_1_3_5');
  	hide('navigation_1_4_1');
  	hide('navigation_1_4_2');
  	hide('navigation_1_4_3');
  	hide('navigation_1_4_4');
  	hide('navigation_1_4_5');
  	hide('navigation_1_5_1');
  	hide('navigation_1_5_2');
  	hide('navigation_1_5_3');
  	hide('navigation_1_5_4');
  	hide('navigation_1_5_5');
	}
	function preLoad(){
	  new Image(200,220).src = 'obr/menu_podklad_05.gif';
	  new Image(200,220).src = 'obr/menu_podklad_06.jpg';

	}