if (document.images) {

var nav_homeA = new Image()
nav_homeA.src = "images/nav_home_off.gif"
var nav_homeZ = new Image()
nav_homeZ.src = "images/nav_home_on.gif"

var nav_proddetailsA = new Image()
nav_proddetailsA.src = "images/nav_proddetails_off.gif"
var nav_proddetailsZ = new Image()
nav_proddetailsZ.src = "images/nav_proddetails_on.gif"

var nav_corporateA = new Image()
nav_corporateA.src = "images/nav_corporate_off.gif"
var nav_corporateZ = new Image()
nav_corporateZ.src = "images/nav_corporate_on.gif"

var nav_websitesA = new Image()
nav_websitesA.src = "images/nav_websites_off.gif"
var nav_websitesZ = new Image()
nav_websitesZ.src = "images/nav_websites_on.gif"

var nav_clinicalprodA = new Image()
nav_clinicalprodA.src = "images/nav_clinicalprod_off.gif"
var nav_clinicalprodZ = new Image()
nav_clinicalprodZ.src = "images/nav_clinicalprod_on.gif"

var nav_dologinA = new Image()
nav_dologinA.src = "images/nav_dologin_off.gif"
var nav_dologinZ = new Image()
nav_dologinZ.src = "images/nav_dologin_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')
}