var btn_parts = new Image(); btn_parts.src="images/btn_parts_off.jpg";
var btn_forsale = new Image(); btn_forsale.src="images/btn_forsale_off.jpg";
var btn_insp = new Image(); btn_insp.src="images/btn_insp_off.jpg";
var btn_parts = new Image(); btn_parts="images/btn_parts_off.jpg";
var btn_rentals = new Image(); btn_rentals="images/btn_rentals_off.jpg";
var btn_shop = new Image(); btn_shop="images/btn_shop_off.jpg";
var btn_testing = new Image(); btn_testing="images/btn_testing_off.jpg";
var btn_tours = new Image(); btn_tours="images/btn_tours_off.jpg";
function s(img_name, post) {
  if (post == "off"){
    post = "on";
  }else{
    post = "off";
  }
  document.images[img_name].src = "images/btn_" + img_name + "_" + post + ".jpg";
}