var image = new Array();
	for( i = 0 ; i < 21 ; i++ ){
		image[i] = new Image();
	}
	image[1].src= "img/map/001_on.jpg";	
	image[2].src= "img/map/002_on.jpg";
	image[3].src= "img/map/003_on.jpg";
	image[4].src= "img/map/004_on.jpg";
	image[5].src= "img/map/005_on.jpg";
	image[6].src= "img/map/006_on.jpg";
	image[7].src= "img/map/007_on.jpg";
	image[8].src= "img/map/008_on.jpg";
	image[9].src= "img/map/009_on.jpg";

function chgImage(map_img,n){
        document.images[map_img].src=image[n].src;
}