var imglist = new Array(
	"./img/keyvisual_01.jpg",
	"./img/keyvisual_02.jpg",
	"./img/keyvisual_03.jpg",
	"./img/keyvisual_04.jpg",
	"./img/keyvisual_05.jpg",
	"./img/keyvisual_06.jpg" );
var selectnum = Math.floor((Math.random() * 100)) % imglist.length;
var output = "<img src=" + imglist[selectnum] + ">";
document.write(output);