//preload images
		image1 = new Image();
		image1.src = "pics/btn_home.gif";
		image2 = new Image();
		image2.src = "pics/btn_home2.gif";

		image5 = new Image();
		image5.src = "pics/btn_team.gif";
		image6 = new Image();
		image6.src = "pics/btn_team2.gif";
		image7 = new Image();
		image7.src = "pics/btn_massage.gif";
		image8 = new Image();
		image8.src = "pics/btn_massage2.gif";
		image9 = new Image();
		image9.src = "pics/btn_referenzen.gif";
		image10 = new Image();
		image10.src = "pics/btn_referenzen2.gif";
		image11 = new Image();
		image11.src = "pics/btn_kontakt.gif";
		image12 = new Image();
		image12.src = "pics/btn_kontakt2.gif";
		image13 = new Image();
		image13.src = "pics/btn_impressum.gif";
		image14= new Image();
		image14.src = "pics/btn_impressum2.gif";
		image15 = new Image();
		image15.src = "pics/btn_airport.gif";
		image16= new Image();
		image16.src = "pics/btn_airport2.gif";
		image15 = new Image();
		image15.src = "pics/btn_mobile.gif";
		image16= new Image();
		image16.src = "pics/btn_mobile2.gif";
		image15 = new Image();
		image15.src = "pics/btn_square.gif";
		image16= new Image();
		image16.src = "pics/btn_square2.gif";

		//change images
		function changeImg(img_name,img_src)
		{
			document[img_name].src=img_src;
		}