// Cameron Gregory -  http://www.bloke.com/
// http://www.bloke.com/javascript/AdRotation
// Usage:
//  AdRotation(images,urls)
//  AdRotationLong(images,urls,iparams)
//     images		is space or comma separated file list
//     urls		is space or comma separated list of url's
//     iparams		params to add to <img>

function AdRotationLong(images,urls,iparams)
{
/* si: start index 
** i: current index
** ei: end index
** cc: current count
*/
 imageSet = new Array();
 urlSet = new Array();
 si = 0; 
 ci=0;
 cc=0;
 ei = images.length;
  for (i=1;i<ei;i++) {
    if (images.charAt(i) == ' ' || images.charAt(i) == ',') {
      imageSet[cc] = images.substring(si,i);
      cc++;
      si=i+1;
      }
    }
  ind = Math.floor(Math.random() *cc);
 si = 0; 
 ci=0;
 cc=0;
 ei = urls.length;
  for (i=1;i<ei && cc <=ind ;i++) {
    if (urls.charAt(i) == ' ' || urls.charAt(i) == ',') {
      urlSet[cc] = urls.substring(si,i);
      cc++;
      si=i+1;
      }
    }

document.writeln("<a href=\""+urlSet[ind]+"\"><img "+iparams+" src="+imageSet[ind]+" border=1 alt=\""+imageSet[ind]+"\"></a>");
}

function AdRotation(images,urls)
{
  AdRotationLong(images,urls,"border=1 vspace=10 alt=''");
}