if (document.images) {

  home = new Image();
  home.src = "images/inner_nav/home.gif";
  home_on = new Image();
  home_on.src = "images/inner_nav/home_on.gif";

  about = new Image();
  about.src = "images/inner_nav/about.gif";
  about_on = new Image();
  about_on.src = "images/inner_nav/about_on.gif";

  contact = new Image();
  contact.src = "images/inner_nav/contact.gif";
  contact_on = new Image();
  contact_on.src = "images/inner_nav/contact_on.gif";
  
  agent = new Image();
  agent.src = "images/inner_nav/agent.gif";
  agent_on = new Image();
  agent_on.src = "images/inner_nav/agent_on.gif";
  
  mortgage = new Image();
  mortgage.src = "images/inner_nav/mortgage.gif";
  mortgage_on = new Image();
  mortgage_on.src = "images/inner_nav/mortgage_on.gif";
  
  community = new Image();
  community.src = "images/inner_nav/community.gif";
  community_on = new Image();
  community_on.src = "images/inner_nav/community_on.gif";
  
  questions = new Image();
  questions.src = "images/inner_nav/questions.gif";
  questions_on = new Image();
  questions_on.src = "images/inner_nav/questions_on.gif";
    
}

function switchOn(imgName) {
    if (document.images) {
      document[imgName].src = eval(imgName + "_on.src");
    }
}
  
function switchOff(imgName) {
    if (document.images) {
      document[imgName].src = eval(imgName + ".src");
    }
}