if (document.images) {

  index_on 		= new Image();
  internet_on 	= new Image();
  cases_on		= new Image();
  search_on		= new Image();
  about_on 		= new Image();
  mail_on 		= new Image();
  
  index_on.src 	= "http://www.NCSEonline.org/NAE/pix/tab_index_hover.gif";
  internet_on.src	= "http://www.NCSEonline.org/NAE/pix/tab_internet_hover.gif";
  cases_on.src	= "http://www.NCSEonline.org/NAE/pix/tab_cases_hover.gif";
  search_on.src 	= "http://www.NCSEonline.org/NAE/pix/tab_search_hover.gif";
  about_on.src 	= "http://www.NCSEonline.org/NAE/pix/tab_about_hover.gif";
  mail_on.src 	= "http://www.NCSEonline.org/NAE/pix/tab_mail_hover.gif";

  index_off 	= new Image();
  internet_off	= new Image();
  cases_off		= new Image();
  search_off	= new Image();
  about_off		= new Image();
  mail_off		= new Image();

  index_off.src 	= "http://www.NCSEonline.org/NAE/pix/tab_index_inactive.gif";
  internet_off.src= "http://www.NCSEonline.org/NAE/pix/tab_internet_inactive.gif";
  cases_off.src	= "http://www.NCSEonline.org/NAE/pix/tab_cases_inactive.gif";
  search_off.src 	= "http://www.NCSEonline.org/NAE/pix/tab_search_inactive.gif";
  about_off.src 	= "http://www.NCSEonline.org/NAE/pix/tab_about_inactive.gif";
  mail_off.src 	= "http://www.NCSEonline.org/NAE/pix/tab_mail_inactive.gif";
}

function imgOn(imgName) {
  document[imgName].src = eval(imgName + "_on.src");
}

function imgOff(imgName) {
  document[imgName].src = eval(imgName + "_off.src");
}