var imgPath = "images/",
imgNames = [ "01.jpg" , "02.jpg" , "03.jpg" , "04.jpg" , "05.jpg" , "06.jpg" , "07.jpg" , "08.jpg" , "09.jpg" , "10.jpg" , "11.jpg" , "12.jpg" , "13.jpg" ];

function getObj(objId) {
	return document.getElementById(objId);
};

function initPage() {
	oTheImage = getObj("Banner");
	imagesLoaded = 0;
	images2Preload = imgNames.length;
	
	for (var i = 0 ; i < imgNames.length ; i++ ) {
		var newImage = new Image();
	    newImage.onload = function () { imageIsLoaded( this ) };
		newImage.src = imgPath + imgNames[i];
		imageIsLoaded( newImage );
    };
};

function imageIsLoaded(newImage) {
	if ( newImage.alreadyLoaded || newImage.width == 0)
		return true;
		
		newImage.alreadyLoaded = true;
		++imagesLoaded;
		
		var alreadyLoaded = ( 100 * imagesLoaded / images2Preload );

		if ( alreadyLoaded == 100 ) {
			setTimeout("Banner()",5000);
		};
};

function Banner() {
	var zufall = Math.round(Math.random()*images2Preload);
	zufall = zufall - 1
	if(zufall < 0) zufall = 0;
	if(""+ imgPath + imgNames[zufall]+"" == document.getElementById("Banner").src) {
		Banner();
	}else{
		slowToggleOpacity("Banner");
		setTimeout("BannerChange('" + imgNames[zufall] +"')",5000);
	}
}

function BannerChange(objBild) {
	document.getElementById("Banner").src=""+ imgPath + objBild+"";
	slowToggleOpacity("Banner");
	setTimeout("Banner()",5000);
}

window.onload = function() {
	var zufall = Math.round(Math.random()*imgNames.length);
	zufall = zufall - 1
	document.getElementById("Banner").src="images/"+ imgNames[zufall]+"";
	initPage();
}