var btn1_on=new Image();
var btn1_off=new Image();
var btn2_on=new Image();
var btn2_off=new Image();
var btn3_on=new Image();
var btn3_off=new Image();
var btn4_on=new Image();
var btn4_off=new Image();
var btn5_on=new Image();
var btn5_off=new Image();
btn1_on.src="../img/btn_momo_over.gif";
btn1_off.src="../img/btn_momo.gif";
btn2_on.src="../img/btn_tango_over.gif";
btn2_off.src="../img/btn_tango.gif";
btn3_on.src="../img/btn_oningyo_over.gif";
btn3_off.src="../img/btn_oningyo.gif";
btn4_on.src="../img/btn_event_over.gif";
btn4_off.src="../img/btn_event.gif";
btn5_on.src="../img/btn_goannai_over.gif";
btn5_off.src="../img/btn_goannai.gif";

function rollon(targetimage){
	if(targetimage=="menu1"){
		document.images[targetimage].src=btn1_on.src;
	}
}
function rolloff(targetimage){
	if(targetimage=="menu1"){
		document.images[targetimage].src=btn1_off.src;
	}
}
function rollon2(targetimage){
	if(targetimage=="menu2"){
		document.images[targetimage].src=btn2_on.src;
	}
}
function rolloff2(targetimage){
	if(targetimage=="menu2"){
		document.images[targetimage].src=btn2_off.src;
	}
}
function rollon3(targetimage){
	if(targetimage=="menu3"){
		document.images[targetimage].src=btn3_on.src;
	}
}
function rolloff3(targetimage){
	if(targetimage=="menu3"){
		document.images[targetimage].src=btn3_off.src;
	}
}
function rollon4(targetimage){
	if(targetimage=="menu4"){
		document.images[targetimage].src=btn4_on.src;
	}
}
function rolloff4(targetimage){
	if(targetimage=="menu4"){
		document.images[targetimage].src=btn4_off.src;
	}
}
function rollon5(targetimage){
	if(targetimage=="menu5"){
		document.images[targetimage].src=btn5_on.src;
	}
}
function rolloff5(targetimage){
	if(targetimage=="menu5"){
		document.images[targetimage].src=btn5_off.src;
	}
}