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

// standard image switching function
// imgName - the name of the image tag to substitute.
// imgObj - the name of the preloaded image object.

function changeImage(imgName, imgObj) {
	if (loaded == true){
		//if (imgName != hilited) {
			document.images[imgName].src = eval(imgObj+".src");
		//}
	}
}

// preload Navi-Hauptpunkte
var loaded = false;

preload( 'p_101_on', 'images/navi/blau_vorwort.gif');
preload( 'p_101_off', 'images/navi/weiss_vorwort.gif');
preload( 'p_201_on', 'images/navi/blau_vorwort.gif');
preload( 'p_201_off', 'images/navi/weiss_vorwort.gif');
preload( 'p_301_on', 'images/navi/blau_vorwort.gif');
preload( 'p_301_off', 'images/navi/weiss_vorwort.gif');
preload( 'p_401_on', 'images/navi/grau_vorwort.gif');
preload( 'p_401_off', 'images/navi/weiss_vorwort.gif');
preload( 'p_402_on', 'images/navi/grau_einstieg.gif');
preload( 'p_402_off', 'images/navi/weiss_einstieg.gif');
preload( 'p_01_on', 'images/navi/blau_01.gif');
preload( 'p_01_off', 'images/navi/weiss_01.gif');
preload( 'p_02_on', 'images/navi/blau_02.gif');
preload( 'p_02_off', 'images/navi/weiss_02.gif');
preload( 'p_03_on', 'images/navi/blau_03.gif');
preload( 'p_03_off', 'images/navi/weiss_03.gif');
preload( 'p_04_on', 'images/navi/blau_04.gif');
preload( 'p_04_off', 'images/navi/weiss_04.gif');
preload( 'p_05_on', 'images/navi/blau_05.gif');
preload( 'p_05_off', 'images/navi/weiss_05.gif');
preload( 'p_06_on', 'images/navi/blau_06.gif');
preload( 'p_06_off', 'images/navi/weiss_06.gif');
preload( 'p_07_on', 'images/navi/blau_07.gif');
preload( 'p_07_off', 'images/navi/weiss_07.gif');
preload( 'p_08_on', 'images/navi/blau_08.gif');
preload( 'p_08_off', 'images/navi/weiss_08.gif');
preload( 'p_09_on', 'images/navi/blau_09.gif');
preload( 'p_09_off', 'images/navi/weiss_09.gif');
preload( 'p_10_on', 'images/navi/blau_10.gif');
preload( 'p_10_off', 'images/navi/weiss_10.gif');
preload( 'p_11_on', 'images/navi/blau_11.gif');
preload( 'p_11_off', 'images/navi/weiss_11.gif');
preload( 'p_12_on', 'images/navi/blau_12.gif');
preload( 'p_12_off', 'images/navi/weiss_12.gif');
preload( 'p_13_on', 'images/navi/blau_13.gif');
preload( 'p_13_off', 'images/navi/weiss_13.gif');
preload( 'p_14_on', 'images/navi/blau_14.gif');
preload( 'p_14_off', 'images/navi/weiss_14.gif');
preload( 'p_15_on', 'images/navi/blau_15.gif');
preload( 'p_15_off', 'images/navi/weiss_15.gif');
preload( 'p_16_on', 'images/navi/blau_16.gif');
preload( 'p_16_off', 'images/navi/weiss_16.gif');
preload( 'p_17_on', 'images/navi/blau_17.gif');
preload( 'p_17_off', 'images/navi/weiss_17.gif');
preload( 'p_18_on', 'images/navi/blau_18.gif');
preload( 'p_18_off', 'images/navi/weiss_18.gif');
preload( 'p_19_on', 'images/navi/blau_19.gif');
preload( 'p_19_off', 'images/navi/weiss_19.gif');
preload( 'p_20_on', 'images/navi/grau_20.gif');
preload( 'p_20_off', 'images/navi/weiss_20.gif');
preload( 'p_21_on', 'images/navi/grau_21.gif');
preload( 'p_21_off', 'images/navi/weiss_21.gif');
preload( 'p_22_on', 'images/navi/grau_22.gif');
preload( 'p_22_off', 'images/navi/weiss_22.gif');
preload( 'p_23_on', 'images/navi/grau_23.gif');
preload( 'p_23_off', 'images/navi/weiss_23.gif');
preload( 'p_24_on', 'images/navi/grau_24.gif');
preload( 'p_24_off', 'images/navi/weiss_24.gif');
preload( 'p_25_on', 'images/navi/grau_25.gif');
preload( 'p_25_off', 'images/navi/weiss_25.gif');
preload( 'p_26_on', 'images/navi/grau_26.gif');
preload( 'p_26_off', 'images/navi/weiss_26.gif');

preload( 'p_27_on', 'images/navi/kaps_button_2.gif');
preload( 'p_27_off', 'images/navi/kaps_button.gif')
preload( 'p_270_on', 'images/navi/kaps_button_sm_2.gif');
preload( 'p_270_off', 'images/navi/kaps_button_sm.gif')
preload( 'p_271_on', 'images/navi/kaps_button_einf_2.gif');
preload( 'p_271_off', 'images/navi/kaps_button_einf.gif')
preload( 'p_272_on', 'images/navi/kaps_button_kap2_2.gif');
preload( 'p_272_off', 'images/navi/kaps_button_kap2.gif')
preload( 'p_273_on', 'images/navi/kaps_button_kap3_2.gif');
preload( 'p_273_off', 'images/navi/kaps_button_kap3.gif')
preload( 'p_274_on', 'images/navi/kaps_button_kap4_2.gif');
preload( 'p_274_off', 'images/navi/kaps_button_kap4.gif')
preload( 'p_275_on', 'images/navi/kaps_button_kap5_2.gif');
preload( 'p_275_off', 'images/navi/kaps_button_kap5.gif')
preload( 'p_276_on', 'images/navi/kaps_button_kap6_2.gif');
preload( 'p_276_off', 'images/navi/kaps_button_kap6.gif')

preload( 'p_278_on', 'images/navi/kaps_link_nichtfett2.gif');
preload( 'p_278_off', 'images/navi/kaps_link_nichtfett.gif')
preload( 'p_279_on', 'images/navi/kaps_link2.gif');
preload( 'p_279_off', 'images/navi/kaps_link.gif')

loaded = true;

function navout() {
	//alert(hilited)
	imgOut = eval(hilited + "_off.src");
	if (document[hilited] && loaded == true){
		document[hilited].src = imgOut;
	}
}

function bildwechsel(item) {
	if (document.images && hilited != item){
		navout();
		imgActive = eval(item + "_on.src");
		document.images[item].src = imgActive;
		hilited = item;
	}
}

function hilight(item) {
	if (hilited != item){
		imgHi = eval(item + "_on.src");
		document.images[item].src = imgHi;
	}
}

function clearHilight(item) {
	if (hilited != item){
		imgHi = eval(item + "_off.src");
		document.images[item].src = imgHi;
	}
}