function hideLayer() {
	    for (var i = 0; i < arguments.length; i++) {
	        var e = document.getElementById(arguments[i]);
	        e.style.display = 'none';
	    }
	}
	
	function showLayer() {
	    for (var i = 0; i < arguments.length; i++) {
	        var e = document.getElementById(arguments[i]);
	        e.style.display = 'block';
	    }
	}
	/* accende e spegne menu di terzo livello*/

		function hideLevel( _levelId ) {
			var thisLevel = document.getElementById( _levelId );			
			thisLevel.style.display = "none";			
			}	
		
		function showLevel( _levelId ) {
			var thisLevel = document.getElementById( _levelId );
			if ( thisLevel.style.display == "none") {
				thisLevel.style.display = "block";
				}
			else {
				hideLevel( _levelId);
				}
			}	
			
		function randomImgHome(){ 
			var myimages=new Array() 
			myimages[1]="/img/img_hp_01.jpg" 
			myimages[2]="/img/img_hp_02.jpg"
			myimages[3]="/img/img_hp_03.jpg"
			myimages[4]="/img/img_hp_04.jpg"
			myimages[5]="/img/img_hp_05.jpg"
			myimages[6]="/img/img_hp_06.jpg"
			myimages[7]="/img/img_hp_07.jpg"
			myimages[8]="/img/img_hp_08.jpg"
			var ry=Math.floor(Math.random()*myimages.length) 
			if (ry==0) 
			ry=1 
			document.write('<img src="'+myimages[ry]+'" border=0>') 
		}
		
		function randomImgStandard(){ 
			var myimages=new Array() 
			myimages[1]="/img/img_std_01.jpg" 
			myimages[2]="/img/img_std_02.jpg"
			myimages[3]="/img/img_std_03.jpg"
			myimages[4]="/img/img_std_04.jpg"
			myimages[5]="/img/img_std_05.jpg"
			myimages[6]="/img/img_std_06.jpg"
			myimages[7]="/img/img_std_07.jpg"			
			myimages[8]="/img/img_std_08.jpg"			
			var ry=Math.floor(Math.random()*myimages.length) 
			if (ry==0) 
			ry=1 
			document.write('<img src="'+myimages[ry]+'" border=0>') 
		}