<!-- Image files for weather warning image change to key -->
wwchg_h =new Image(); 
<!-- Replacement Image -->
wwchg_h.src = "htm/images/wwkey.gif";
wwchg_nh = new Image(); 
<!-- Original Image -->
wwchg_nh.src = "http://www.metoffice.gov.uk//weather/images/warnings/yh_d1.gif";
function wwchgover() {
document.wwchg.src=wwchg_h.src;
}
function wwchgout() {
document.wwchg.src=wwchg_nh.src;
}