ppage = "\index.html"
npage = "page1.html"
prefix = "page"
suffix = ".html"
min = 1
max = 16
target = top
fName = document.location.href
n = eval(fName.substring(fName.lastIndexOf(prefix)+prefix.length,fName.lastIndexOf(suffix)))
prev = n-1
next = n+1

if (prev >= min && prev < max) {
 ppage = prefix + prev + suffix
 target = top
 }

if (next <= max && next > min) {
 npage = prefix + next + suffix
 target = top
 }

function move(page) {
 target.location = page
 }