/* 設定部分 */
var interval = 5000; //切り替わる時間（1000=1秒）
var imgs = new Array(); var hrefs = new Array();
imgs[0] = new Image(); imgs[0].src = "image/title-image00.png"; hrefs[0] = "http://www.kitanosho.com/web-consulting.html";
imgs[1] = new Image(); imgs[1].src = "image/title-image01.png"; hrefs[1] = "http://www.kitanosho.com/hp-seisaku-top.html";
imgs[2] = new Image(); imgs[2].src = "image/title-image02.png"; hrefs[2] = "http://www.kitanosho.com/hp-jirei.html";
imgs[3] = new Image(); imgs[3].src = "image/title-image03.png"; hrefs[3] = "http://www.kitanosho.com/works.html";

/* プログラム部分 */
var num = Math.floor(Math.random()*imgs.length);
document.write('<a href="'+hrefs[num]+'" id="cth"><img src="'+imgs[num].src+'" id="cti" style="border:0" /></a>');
var cti = document.getElementById("cti"); var cth = document.getElementById("cth");
setInterval(function(){
num += Math.floor(Math.random()*(imgs.length-1))+1;
if(num>=imgs.length) num -= imgs.length;
cti.src = imgs[num].src; cth.href = hrefs[num];
},interval);