var imgPath = '/img/rotation/';

var images = new Array();
images.push('topimg_21cmm01.jpg');
images.push('topimg_21cmm02.jpg');
images.push('topimg_ghost01.jpg');
images.push('topimg_ghost02.jpg');
images.push('topimg_nakanaide02.jpg');
images.push('topimg_prince02.jpg');
images.push('topimg_nanatu05.jpg');
images.push('topimg_mm01.jpg');
images.push('topimg_mm02.jpg');
images.push('topimg_mm03.jpg');
images.push('topimg_mm04.jpg');
images.push('topimg_mm05.jpg');
images.push('topimg_mm06.jpg');
images.push('topimg_shabon01.jpg');
images.push('topimg_shabon02.jpg');
images.push('topimg_shabon03.jpg');
images.push('topimg_shabon04.jpg');
images.push('topimg_shabon05.jpg');
images.push('topimg_shabon06.jpg');
images.push('topimg_shabon07.jpg');
images.push('topimg_shabon08.jpg');
images.push('topimg_bochan01.jpg');
images.push('topimg_bochan02.jpg');
images.push('topimg_bochan03.jpg');

var imgRandom = Math.floor(Math.random() * images.length);

document.write('<img src="'+imgPath+images[imgRandom]+'">');