function showm(element){
		if (element == 'm1'){
			document.getElementById('menu1').style.visibility = 'visible';
			document.getElementById('menu2').style.visibility = 'hidden';
			document.getElementById('menu3').style.visibility = 'hidden';
		}
		if (element == 'm2'){
			document.getElementById('menu1').style.visibility = 'hidden';
			document.getElementById('menu2').style.visibility = 'visible';
			document.getElementById('menu3').style.visibility = 'hidden';
		}			
		if (element == 'm3'){
			document.getElementById('menu1').style.visibility = 'hidden';
			document.getElementById('menu2').style.visibility = 'hidden';
			document.getElementById('menu3').style.visibility = 'visible';
		}
		if (element == 'clear'){
			document.getElementById('menu1').style.visibility = 'hidden';
			document.getElementById('menu2').style.visibility = 'hidden';
			document.getElementById('menu3').style.visibility = 'hidden';
		}					
	}