var alertTimerId = null;

function products_on() {
all_off();
document.getElementById('menu_products').style.visibility = '';
alertTimerId = setTimeout("time_out()",3000);
}

function distributors_on() {
all_off();
document.getElementById('menu_distributors').style.visibility = '';
alertTimerId = setTimeout("time_out()",3000);
}

function oem_on() {
all_off();
document.getElementById('menu_oem').style.visibility = '';
alertTimerId = setTimeout("time_out()",3000);
}

function support_on() {
all_off();
document.getElementById('menu_support').style.visibility = '';
alertTimerId = setTimeout("time_out()",3000);
}

function time_out() {
all_off();
}

function all_off() {
if (alertTimerId != null) {
    clearTimeout(alertTimerId);
    alertTimerId = null;
}
document.getElementById('menu_products').style.visibility = 'hidden';
document.getElementById('menu_distributors').style.visibility = 'hidden';
document.getElementById('menu_oem').style.visibility = 'hidden';
document.getElementById('menu_support').style.visibility = 'hidden';
}	

all_off();