if (document.images) {

nav_homon = new Image();
nav_homon.src = "images/nav_hom2.gif";
nav_homoff = new Image();
nav_homoff.src = "images/nav_hom.gif";

nav_rooon = new Image();
nav_rooon.src = "images/nav_roo2.gif";
nav_roooff = new Image();
nav_roooff.src = "images/nav_roo.gif";

nav_reson = new Image();
nav_reson.src = "images/nav_res2.gif";
nav_resoff = new Image();
nav_resoff.src = "images/nav_res.gif";

nav_locon = new Image();
nav_locon.src = "images/nav_loc2.gif";
nav_locoff = new Image();
nav_locoff.src = "images/nav_loc.gif";

nav_diron = new Image();
nav_diron.src = "images/nav_dir2.gif";
nav_diroff = new Image();
nav_diroff.src = "images/nav_dir.gif";

nav_aboon = new Image();
nav_aboon.src = "images/nav_abo2.gif";
nav_abooff = new Image();
nav_abooff.src = "images/nav_abo.gif";

nav_wedon = new Image();
nav_wedon.src = "images/nav_wed2.gif";
nav_wedoff = new Image();
nav_wedoff.src = "images/nav_wed.gif";

nav_speon = new Image();
nav_speon.src = "images/nav_spe2.gif";
nav_speoff = new Image();
nav_speoff.src = "images/nav_spe.gif";

}

function imgOn(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "on.src");       
}
}

function imgOff(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "off.src");        
}
}