if(document.images){
  var imgOn = new Array(5);
  var imgOff = new Array(5);
  
  imgOn[0] = new Image();
  imgOn[1] = new Image();
  imgOn[2] = new Image();
  imgOn[3] = new Image();
  imgOn[4] = new Image();
 
  imgOff[0] = new Image();
  imgOff[1] = new Image();
  imgOff[2] = new Image();
  imgOff[3] = new Image();
  imgOff[4] = new Image();
 
  imgOn[0].src = "images/lifestyle_btn_on.gif";
  imgOn[1].src = "images/homedesigns_btn_on.gif";
  imgOn[2].src = "images/developers_btn_on.gif";
  imgOn[3].src = "images/contact_btn_on.gif";
  imgOn[4].src = "images/btm_nav_on.gif";
  
  imgOff[0].src = " images/lifestyle_btn_off.gif ";
  imgOff[1].src = " images/homedesigns_btn_off.gif ";
  imgOff[2].src = " images/developers_btn_off.gif";
  imgOff[3].src = " images/contact_btn_off.gif ";
  imgOff[4].src = " images/btm_nav.gif ";

  }
  
  function on(imgNumber){
  if(document.images)
  // array numbers start at zero but we want to start numbering at one,
  //so thats why we subtract one from the imgNumber
  document[imgNumber].src = imgOn[imgNumber].src;
  	
  }
  function off(imgNumber){
 if(document.images)
  document[imgNumber].src = imgOff[imgNumber].src;

}