var browserOK = false;
  var pics;
  browserOK = true;
  pics = new Array();
  var objCount = 0;
  function preload(name, first, second) {
    if (browserOK) {
      pics[objCount] = new Array(3);
      pics[objCount][0] = new Image();
      pics[objCount][0].src = first;
      pics[objCount][1] = new Image();
      pics[objCount][1].src = second;
      pics[objCount][2] = name;
      objCount++;
    }
  }
  function on(name){
    if (browserOK) {
       for (i = 0; i < objCount; i++) {
        if (document.images[pics[i][2]] != null) {
          if (name != pics[i][2]) {
            document.images[pics[i][2]].src = pics[i][0].src;
          }
          else {
             document.images[pics[i][2]].src = pics[i][1].src;
          }
        }
      }
    }
  }
  function off(){
    if (browserOK) {
       for (i = 0; i < objCount; i++) {
        if (document.images[pics[i][2]] != null) {
          document.images[pics[i][2]].src = pics[i][0].src;
        }
      }
    }
  }

  preload("home", "images/left_button_home.gif", "images/left_button_home02.gif");
  preload("about_NHB", "images/left_button_about_NHB.gif", "images/left_button_about_NHB02.gif");
  preload("benefits", "images/left_button_benefits.gif", "images/left_button_benefits02.gif");
  preload("costs", "images/left_button_costs.gif", "images/left_button_costs02.gif");
  preload("savings", "images/left_button_savings.gif", "images/left_button_savings02.gif");
  preload("simple_to_use", "images/left_button_simple_to_use.gif", "images/left_button_simple_to_use02.gif");
  preload("contact_us", "images/left_button_contact_us.gif", "images/left_button_contact_us02.gif");
  preload("enroll_now", "images/left_button_enroll_now.gif", "images/left_button_enroll_now02.gif");