I purchased JS background image rotator that works but I want the image to scale to the width of the browser window. My html page links to a JS doc called "rotator.js" that has the following code:

var back=[];
back[0] = ["http://thechesapeakeinn.com/1.jpg"];
back[1] = ["http://thechesapeakeinn.com/2.jpg"];
back[2] = ["http://thechesapeakeinn.com/3.jpg"];
back[1] = ["http://thechesapeakeinn.com/3.jpg"];
back[2] = ["http://thechesapeakeinn.com/3.jpg"];
back[3] = ["http://thechesapeakeinn.com/1.jpg"];
back[4] = ["http://thechesapeakeinn.com/2.jpg"];
back[5] = ["http://thechesapeakeinn.com/3.jpg"];
back[6] = ["http://thechesapeakeinn.com/1.jpg"];
back[7] = ["http://thechesapeakeinn.com/3.jpg"];
back[8] = ["http://thechesapeakeinn.com/3.jpg"];
back[9] = ["http://thechesapeakeinn.com/1.jpg"];
back[10] = ["http://thechesapeakeinn.com/3.jpg"];
back[11] = ["http://thechesapeakeinn.com/3.jpg"];
back[12] = ["http://thechesapeakeinn.com/3.jpg"];
back[13] = ["http://thechesapeakeinn.com/3.jpg"];
back[14] = ["http://thechesapeakeinn.com/3.jpg"];
back[15] = ["http://thechesapeakeinn.com/3.jpg"];
back[16] = ["http://thechesapeakeinn.com/3.jpg"];
back[17] = ["http://thechesapeakeinn.com/3.jpg"];
back[18] = ["http://thechesapeakeinn.com/3.jpg"];
back[19] = ["http://thechesapeakeinn.com/3.jpg"];
back[20] = ["http://thechesapeakeinn.com/3.jpg"];
back[21] = ["http://thechesapeakeinn.com/3.jpg"];
back[22] = ["http://thechesapeakeinn.com/3.jpg"];
back[23] = ["http://thechesapeakeinn.com/3.jpg"];



function backgroundimg(){
document.getElementById("back").style.background = 'black url('+ back[new Date().getHours()] +') no-repeat';
setTimeout('backgroundimg()',60000);}

and in the body of my html page I have:

<div id="back" style=" position:fixed; top:0; left:0; height:100%; width:100%">
<script type="text/javascript">backgroundimg()</script>
</div>

Is there a way to make the image width fit the browser window?

Thanks for you help,