var img1on = new Image();
    img1on.src="/images/home_on.jpg";
var img1off = new Image();
    img1off.src="/images/home_off.jpg";
var img2on = new Image();
    img2on.src="/images/service_on.jpg";
var img2off = new Image();
    img2off.src="/images/service_off.jpg";
var img3on = new Image();
    img3on.src="/images/contact_on.jpg";
var img3off = new Image();
    img3off.src="/images/contact_off.jpg";
var img3on = new Image();
    img3on.src="/images/about_on.jpg";
var img3off = new Image();
    img3off.src="/images/about_off.jpg";

function navchange(state,img) {
	document.images[img].src="/images/"+img+"_"+state+".jpg";  
}