var acnt = 1;

function slide() { //slide changer function
  if (acnt >= arr_len) {
	// return to first slide image
	acnt = 0;
  }
  document.slide.src = presentation[acnt].src;
  document.getElementById('caption').innerHTML = caption[acnt];
  acnt++;
  
  window.setTimeout("slide()", 7000);
}

//calls the achangeSlide() function every 8 seconds	 slide.filters[0].Apply();
//change the timer as necessary (minutes * 60000) or (seconds * 1000)	 slide.filters[0].Play();
//var speed = window.setInterval("slide()", 7000);
var speed = window.setTimeout("slide()", 10000);