if (document.images) {

var topnav_homeA = new Image()
topnav_homeA.src = "images/topnav_home_off.gif"
var topnav_homeZ = new Image()
topnav_homeZ.src = "images/topnav_home_on.gif"

var topnav_aboutA = new Image()
topnav_aboutA.src = "images/topnav_about_off.gif"
var topnav_aboutZ = new Image()
topnav_aboutZ.src = "images/topnav_about_on.gif"

var topnav_toolsA = new Image()
topnav_toolsA.src = "images/topnav_tools_off.gif"
var topnav_toolsZ = new Image()
topnav_toolsZ.src = "images/topnav_tools_on.gif"

var topnav_constructionA = new Image()
topnav_constructionA.src = "images/topnav_construction_off.gif"
var topnav_constructionZ = new Image()
topnav_constructionZ.src = "images/topnav_construction_on.gif"

var topnav_sunpassA = new Image()
topnav_sunpassA.src = "images/topnav_sunpass_off.gif"
var topnav_sunpassZ = new Image()
topnav_sunpassZ.src = "images/topnav_sunpass_on.gif"

var topnav_safetyA = new Image()
topnav_safetyA.src = "images/topnav_safety_off.gif"
var topnav_safetyZ = new Image()
topnav_safetyZ.src = "images/topnav_safety_on.gif"

var topnav_businessA = new Image()
topnav_businessA.src = "images/topnav_business_off.gif"
var topnav_businessZ = new Image()
topnav_businessZ.src = "images/topnav_business_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')
}