var preloadArray = new Array();
var preloadArrayLength = 0;
function preloadImages() {
	if (document.images) {
		var imgFiles = preloadImages.arguments;
		for (var i=0; i<imgFiles.length; i++) {
	    	preloadArray[preloadArrayLength] = new Image;
		    preloadArray[preloadArrayLength].src = imgFiles[i];
            preloadArrayLength++;
		}
	}
}

if (document.images) {
preloadImages("../navi_pics/dachbau_on.gif","../navi_pics/fassaden_on.gif","../navi_pics/dachfl_on.gif","../navi_pics/email_on.gif");
}

var standard= new Array
("dachbau","fassaden","dachfl","email");

function imgOn(imgName) {
        if (document.images) {
			    for(i=0;i<standard.length;i++){
				  document[standard[i]].src ="../navi_pics/" + standard[i]+".gif";
			}			
			document[imgName].src = "../navi_pics/"+imgName+"_on.gif";
        }
}

function imgOff(imgName) {
        if (document.images) {			
			document[imgName].src = "../navi_pics/"+imgName+".gif";
        }
}