function preload(imgName,imgSrc) {
         if (document.images) {
         eval(imgName+' = new Image()')
         eval(imgName+'.src = "'+imgSrc+'"')
            }
}

preload('nav2on','/images/nav_gsiebdruck_1.gif')
preload('nav2off','/images/nav_gsiebdruck_2.gif')

preload('nav3on','/images/nav_tsiebdruck_1.gif')
preload('nav3off','/images/nav_tsiebdruck_2.gif')

preload('nav4on','/images/nav_dienst_1.gif')
preload('nav4off','/images/nav_dienst_2.gif')

preload('nav5on','/images/nav_referenzen_1.gif')
preload('nav5off','/images/nav_referenzen_2.gif')

preload('nav6on','/images/nav_technik_1.gif')
preload('nav6off','/images/nav_technik_2.gif')

preload('nav7on','/images/nav_wir_1.gif')
preload('nav7off','/images/nav_wir_2.gif')

preload('nav8on','/images/nav_kontakt_1.gif')
preload('nav8off','/images/nav_kontakt_2.gif')

function imgOff(imgName) {
		 if(navigator.appVersion >= '4'){
		 if (document.images) {
		 document["nav"+imgName].src = eval("nav"+imgName + "off.src");
		}
  	}}


function imgOn(imgName) {
		 if(navigator.appVersion >= '4'){
		 if (document.images) {
		 document["nav"+imgName].src = eval("nav"+imgName + "on.src");
		 }
	}}