function init(){
    
	document.getElementById("bt01").onmouseover = function(){
		document.getElementById("submenu1").style.display = 'block';
	}; 
	document.getElementById("bt01").onmouseout = function(){
		document.getElementById("submenu1").style.display = 'none';
	}; 
	document.getElementById("submenu1").onmouseover = function(){
		document.getElementById("submenu1").style.display = 'block';
	}; 
	document.getElementById("submenu1").onmouseout = function(){
		document.getElementById("submenu1").style.display = 'none';
	};
	document.getElementById("bt02").onmouseover = function(){
		document.getElementById("submenu2").style.display = 'block';
	}; 
	document.getElementById("bt02").onmouseout = function(){
		document.getElementById("submenu2").style.display = 'none';
	}; 
	document.getElementById("submenu2").onmouseover = function(){
		document.getElementById("submenu2").style.display = 'block';
	}; 
	document.getElementById("submenu2").onmouseout = function(){
		document.getElementById("submenu2").style.display = 'none';
	};	

}
window.onload=init