var pre1 = new Image();
pre1.src = 'images/home_on.gif';

var pre2 = new Image();
pre2.src = 'images/menu_on.gif';

var pre3 = new Image();
pre3.src = 'images/directions_on.gif';

var pre4 = new Image();
pre4.src = 'images/about_on.gif';



function globalOver(navimg) {
if(document.images) {
document.images[navimg].src = 'images/'+navimg+'_on.gif';
}
}

function globalOut(navimg) {
if(document.images) {
document.images[navimg].src = 'images/'+navimg+'_off.gif';
}
}

// onMouseOver="globalOver('')" onMouseOut="globalOut('')"><img name=""