if (document.images) {

       
        button1on = new Image()
        button1on.src = "nav/abouton.gif"
        button2on = new Image()
        button2on.src = "nav/mapon.gif"
        button3on = new Image()
        button3on.src = "nav/contacton.gif"
        button4on = new Image()
        button4on.src = "nav/homeon.gif"
        button5on = new Image()
        button5on.src = "nav/storeon.gif"

              
        button1off = new Image()
        button1off.src = "nav/aboutoff.gif"
        button2off = new Image()
        button2off.src = "nav/mapoff.gif"
        button3off = new Image()
        button3off.src = "nav/contactoff.gif"
        button4off = new Image()
        button4off.src = "nav/homeoff.gif"
        button5off = new Image()
        button5off.src = "nav/storeoff.gif"
	
         }

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

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