function newRollover(imgName,imgFiles) {
  if (document.images) {
    imgFiles=imgFiles+",";
    imgNo=1;
    while(imgFiles.indexOf(',')!=-1) {
      imgFile=imgFiles.substring(0,imgFiles.indexOf(','));
      imgFiles=imgFiles.substring(imgFiles.indexOf(',')+1,imgFiles.length);
      eval(imgName+"_urc_"+imgNo+"=new Image();");
      eval(imgName+"_urc_"+imgNo+".src='"+imgFile+"'");
      imgNo++;
    }
  }
}

function roll(img,on) {
  if (document.images)
    eval("document.images['"+img+"'].src="+img+"_urc_"+on+".src");
}

//template
newRollover("horn","images/template/header_horn_off.gif,images/template/header_horn_over.gif");