// main navigation rollover
function homeNavOn(id) {
    var top_cell = document.getElementById("top_cell");
    var bot_cell = document.getElementById("bot_cell_" + id);

    top_cell.className = "top_over_" + id;
    bot_cell.style.backgroundImage = "url(home_bot_over_" + id + ".gif)";
}

// main navigation rollout
function homeNavOff(id) {
    var top_cell = document.getElementById("top_cell");
    var bot_cell = document.getElementById("bot_cell_" + id);

    top_cell.className = "";
    bot_cell.style.backgroundImage = "";
}

// preload rollover images
top_over_1 = new Image();
top_over_1.src = "home_top_over_1.gif";
top_over_2 = new Image();
top_over_2.src = "home_top_over_2.gif";
top_over_3 = new Image();
top_over_3.src = "home_top_over_3.gif";
top_over_4 = new Image();
top_over_4.src = "home_top_over_4.gif";
top_over_5 = new Image();
top_over_5.src = "home_top_over_5.gif";
top_over_6 = new Image();
top_over_6.src = "home_top_over_6.gif";
top_over_7 = new Image();
top_over_7.src = "home_top_over_7.gif";

bot_over_1 = new Image();
bot_over_1.src = "home_bot_over_1.gif";
bot_over_2 = new Image();
bot_over_2.src = "home_bot_over_2.gif";
bot_over_3 = new Image();
bot_over_3.src = "home_bot_over_3.gif";
bot_over_4 = new Image();
bot_over_4.src = "home_bot_over_4.gif";
bot_over_5 = new Image();
bot_over_5.src = "home_bot_over_5.gif";
bot_over_6 = new Image();
bot_over_6.src = "home_bot_over_6.gif";
bot_over_7 = new Image();
bot_over_7.src = "home_bot_over_7.gif";