var ad = new Array()
ad[0] = "adfiles/multiAd_oReilly/ad_oreilly00.js";
ad[1] = "adfiles/multiAd_oReilly/ad_oreilly01.js";
ad[2] = "adfiles/multiAd_oReilly/ad_oreilly02.js";
ad[3] = "adfiles/multiAd_oReilly/ad_oreilly03.js";
ad[4] = "adfiles/multiAd_oReilly/ad_oreilly04.js";



var p = ad.length;

var whichAd = Math.round(Math.random()*(p-1));

var newAd = ad[whichAd];

document.write(' <script src="' + newAd + '"></script> ');