function navTabFindDefault(li, className) {
    var node = li.previousSibling;
    while (node) { if (node.className == className) return node; node = node.previousSibling; }
    node = li.nextSibling;
    while (node) { if (node.className == className) return node; node = node.nextSibling;}
    return null;
}
function navTabMouseOver(li) {
    var defNode = navTabFindDefault(li, "nav_default_on");
    if (defNode)
        defNode.className = "nav_default_off";
    li.className = "mouse_over";
}
function navTabMouseOut(li) {
    li.className = "";
    var defNode = navTabFindDefault(li, "nav_default_off");
    if (defNode)
        defNode.className = "nav_default_on";
}