var c=1;
var t;
var timer_is_on=0;

function timedCount()
{
document.getElementById('content').style.backgroundImage="url('/images/PR_rotating"+c+".jpg')";

c=c+1;
if (c >= 6) {
  c = 1;
}
t=setTimeout("timedCount()",8000);
}

function doTimer()
{

if (!timer_is_on)
  {
  timer_is_on=1;
  timedCount();
  }
}