var imageheight = 300;
var imagewidth = 1835;
var movesize = 1;
var speed = 20;

var left = 0;
var right;
var timer;
var dir = 0;

function scrollLeft() {
	window.panFrame.scrollBy(-1,0);
}

function scrollRight() {
	window.panFrame.scrollBy(1,0);
}

function panImage() {
	if(dir == 0) {  
    	if(left < imagewidth - (imageheight + movesize)) {
      		left += movesize;
			scrollRight();
    	}
    	else {
      		dir = 1;
    	}
  	}
  	else if(dir == 1) {  
    	if(left > movesize) {
      		left -= movesize;
			scrollLeft();
    	}
    	else {
     		dir = 0;
    	}
  	}
	right = left + imageheight;

 	timer = setTimeout("panImage()",speed);
}