Image slideshow using JavaScript

<script language="JavaScript" type="text/javascript">
var count = 0
var images = new Array('morning.jpg','afternoon.jpg','night.jpg','lightbulb_on.jpg')

function slideShow(direction){

 if (direction == 'next' && count <=2){
 count++
 }

 if (direction == 'back' && count >=1){
 count --;
 }

  document.getElementById("show").innerHTML = (count+1)+" of 4 <br> <img src='images/"+images[count]+"'>"
}  
</script>