if (document.images) {

var nav_aboutA = new Image()
nav_aboutA.src = "images/nav_about_off.gif"
var nav_aboutZ = new Image()
nav_aboutZ.src = "images/nav_about_on.gif"

var nav_mapA = new Image()
nav_mapA.src = "images/nav_map_off.gif"
var nav_mapZ = new Image()
nav_mapZ.src = "images/nav_map_on.gif"

var nav_faqA = new Image()
nav_faqA.src = "images/nav_faq_off.gif"
var nav_faqZ = new Image()
nav_faqZ.src = "images/nav_faq_on.gif"

var nav_advertiseA = new Image()
nav_advertiseA.src = "images/nav_advertise_off.gif"
var nav_advertiseZ = new Image()
nav_advertiseZ.src = "images/nav_advertise_on.gif"

var nav_contactA = new Image()
nav_contactA.src = "images/nav_contact_off.gif"
var nav_contactZ = new Image()
nav_contactZ.src = "images/nav_contact_on.gif"

}
function act(imgName) {
if (document.images)
document[imgName].src = eval(imgName + 'Z.src')
}

function inact(imgName) {
if (document.images)
document[imgName].src = eval(imgName + 'A.src')
}