function setbanner(){
var jumpurl = new Array(); 
var imgname = new Array(); 
var a = new Array();

imgname[0]="36.gif";
imgname[1]="31.gif";
imgname[2]="21.gif";
imgname[3]="40.jpg";


jumpurl[0]="http://med.eizojoho.co.jp/";
jumpurl[1]="http://www.mavic.ne.jp/index.php/module/Forum";
jumpurl[2]="http://www.eizojoho.co.jp";
jumpurl[3]="http://www.mavic.ne.jp/index.php/module/Topic/action/Show?tid=126";


n = Math.floor(Math.random()*jumpurl.length); 

a[0] = jumpurl[n];
a[1] = imgname[n];

return a;
}