Javascript not loading (why?)

<script type="javascript" src="main-img-rotator.js"></script>

var howOften = 5; //number often in seconds to rotate
var current = 0; //start the counter at 0
var ns6 = document.getElementById&&!document.all; //detect netscape 6

// place your images, text, etc in the array elements here
var items = new Array();
    items[0]="<a href='link.htm' ><img alt='image0 (9K)' src='img-rot-01.jpg' border='0' /></a>"; //a linked image
    items[1]="<a href='link.htm'><img alt='image1 (9K)' src='img-rot-02.jpg' border='0' /></a>"; //a linked image
    items[2]="<a href='link.htm'><img alt='image2 (9K)' src='img-rot-03.jpg' border='0' /></a>"; //a linked image
    items[3]="<a href='link.htm'><img alt='image3 (9K)' src='img-rot-04.jpg' border='0' /></a>"; //a linked image
    items[4]="<a href='link.htm'><img alt='image4 (9K)' src='img-rot-05.jpg' border='0' /></a>"; //a linked image
    items[5]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-06.jpg' border='0' /></a>"; //a linked image
	items[6]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-07.jpg' border='0' /></a>"; //a linked image
	items[7]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-08.jpg' border='0' /></a>"; //a linked image
	items[8]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-09.jpg' border='0' /></a>"; //a linked image
    items[9]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-10.jpg' border='0' /></a>"; //a linked image
	items[10]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-11.jpg' border='0' /></a>"; //a linked image
	items[11]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-12.jpg' border='0' /></a>"; //a linked image
	items[12]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-13.jpg' border='0' /></a>"; //a linked image
    items[13]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-14.jpg' border='0' /></a>"; //a linked image
	items[14]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-15.jpg' border='0' /></a>"; //a linked image
	items[15]="<a href='link.htm'><img alt='image5 (18K)' src='img-rot-16.jpg' border='0' /></a>"; //a linked image
function rotater() {
    document.getElementById("placeholder").innerHTML = items[current];
    current = (current==items.length-1) ? 0 : current + 1;
    setTimeout("rotater()",howOften*1000);
}

function rotater() {
    if(document.layers) {
        document.placeholderlayer.document.write(items[current]);
        document.placeholderlayer.document.close();
    }
    if(ns6)document.getElementById("placeholderdiv").innerHTML=items[current]
        if(document.all)
            placeholderdiv.innerHTML=items[current];

    current = (current==items.length-1) ? 0 : current + 1; //increment or reset
    setTimeout("rotater()",howOften*1000);
}
window.onload=rotater;
//-->