TOP /すぐに使えるJavaScript リンクをランダムに表示(時間が変わるまで入れ替えない)

HIMAJIN
icon-kan
pastel
オルゴールの城

<script type="text/javascript"><!--
link=new Array();
link[0]=["../../index.html","himajin.gif","HIMAJIN"];
link[1]=["http://www.nagai.net/icon-kan/index.html","ickna.gif","icon-kan"];
link[2]=["http://pastel.oheya.jp/","pb2.gif","pastel"];
link[3]=["http://www.sora-aonami.com/index.html","yakata2.gif","オルゴールの城"];
    //増やす時は link[連番]=["リンクアドレス","画像アドレス","チップテキスト"];
//-------------------------------------------------------
random_set=new Array();
for (i = 0; i < link.length; i++)
random_set[i]=i;
var sethour;
theName="linkimg=";
setDay=new Date();

function cook_get(){
  theCookie=document.cookie+";";
  start=theCookie.indexOf(theName);
if(start !=-1){
  end=theCookie.indexOf(";",start);
  theData=unescape(theCookie.substring(start+theName.length,end));
  setlink=theData.match(/[^@]+/g);
  sethour=setlink[link.length];
}
linkchange();
}

function linkchange(){
  if(sethour!=setDay.getHours()){
     shuffle();
   }else{
     for (i = 0; i < random_set.length; i++)
         random_set[i]=setlink[i];
   }
     for (i = 0; i < random_set.length; i++){
         document.images["img"+i].src=link[random_set[i]][1];
         document.images["img"+i].alt=link[random_set[i]][2];
         document.getElementById("link"+i).href=link[random_set[i]][0];
     }
}

function shuffle(){
for (i = 0; i < random_set.length; i++) {
        setin = random_set.length - i;
        myrand=Math.floor(Math.random()*setin);
        mytext=random_set[myrand];
        for(j=myrand ; j < random_set.length-1; j++)random_set[j]=random_set[j+1];
        random_set[random_set.length-1]=mytext;
    }
}

function cook_set(){
  sethour=setDay.getHours();
  myData="";
for (i = 0; i < random_set.length; i++)
     myData+=random_set[i]+"@";
  myData+=sethour;
  setDay.setTime(setDay.getTime()+(1000*60*60*23));
  document.cookie=theName+escape(myData)+";expires="+setDay.toGMTString();
}
window.onload =cook_get;
window.onunload =cook_set;
/*himajin.moo.jp*/
// --></script>
<table>
<tr><td>
<a href="../../index.html"id="link0"><img src="himajin.gif"name="img0"alt="HIMAJIN"border=0></a>
</td></tr>
<tr><td>
<a href="http://www.nagai.net/icon-kan/index.html"id="link1"><img src="ickna.gif"name="img1"alt="icon-kan"border=0></a>
</td></tr>
<tr><td>
<a href="http://pastel.oheya.jp/"id="link2"><img src="pb2.gif"name="img2"alt="pastel"border=0></a>
</td></tr>
<tr><td>
<a href="http://www.sora-aonami.com/index.html"id="link3"><img src="yakata2.gif"name="img3"alt="オルゴールの城"border=0></a>
</td></tr>
</table>