function globalNavigation(ClientID) {
    var nav = document.getElementById(ClientID).getElementsByTagName("li");
    for (var i = 0; i < nav.length; i++) {
        globalNavHover(nav[i]);
    }
}

function globalNavHover(item) {
    var img = item.getElementsByTagName("img")[0];
    if (img.src.match("selected")) {
        return;
    }
    item.onmouseover = function() {
        img.src = img.src.replace(".gif", "_hover.gif");
    }
    item.onmouseout = function() {
        img.src = img.src.replace("_hover.gif", ".gif");
    }
}