preloadFlag = false;
				
				function preloadImages() {
					if (document.images) {
						
						img1on = new Image();
						img1on.src = "_images/nav/home_on.gif";
						img2on = new Image();
						img2on.src = "_images/nav/about_on.gif";
						img3on = new Image();
						img3on.src = "_images/nav/services_on.gif";
						img4on = new Image();
						img4on.src = "_images/nav/faq_on.gif";
						img5on = new Image();
						img5on.src = "_images/nav/contact_on.gif";
						
						imgaon = new Image();
						imgaon.src = "_images/nav/s_overview_on.gif";
						imgbon = new Image();
						imgbon.src = "_images/nav/s_rodents_on.gif";
						imgcon = new Image();
						imgcon.src = "_images/nav/s_insects_on.gif";
						imgdon = new Image();
						imgdon.src = "_images/nav/s_bats_on.gif";
						
						img1off = new Image();
						img1off.src = "_images/nav/home_off.gif";
						img2off = new Image();
						img2off.src = "_images/nav/about_off.gif";
						img3off = new Image();
						img3off.src = "_images/nav/services_off.gif";
						img4off = new Image();
						img4off.src = "_images/nav/faq_off.gif";						
						img5off = new Image();
						img5off.src = "_images/nav/contact_off.gif";
						
						imgaoff = new Image();
						imgaoff.src = "_images/nav/s_overview_off.gif";
						imgboff = new Image();
						imgboff.src = "_images/nav/s_rodents_off.gif";
						imgcoff = new Image();
						imgcoff.src = "_images/nav/s_insects_off.gif";
						imgdoff = new Image();
						imgdoff.src = "_images/nav/s_bats_off.gif";
						
						preloadFlag = true;
					}
				}
				function imgOn(imgName) {
					if (preloadFlag == true) {
						document[imgName].src = eval(imgName + "on.src");
						}
				}
				function imgOff(imgName) {
					if (preloadFlag == true) {
						document[imgName].src = eval(imgName + "off.src");
						}
				}