function mouseOver01(){
	document.getElementById("button01").src = "button01_over.png";
}
		
function mouseOut01(){
	document.getElementById("button01").src = "button01.png";
}

function mouseOver02(){
	document.getElementById("button02").src = "button02_over.png";
}
		
function mouseOut02(){
	document.getElementById("button02").src = "button02.png";
}

function mouseOver03(){
	document.getElementById("button03").src = "button03_over.png";
}
		
function mouseOut03(){
	document.getElementById("button03").src = "button03.png";
}

function mouseOver04(){
	document.getElementById("button04").src = "button04_over.png";
}
		
function mouseOut04(){
	document.getElementById("button04").src = "button04.png";
}