if (document.images) {
     button1 = new Image
     button2 = new Image
     button3 = new Image
     button4 = new Image
     button5 = new Image
     button6 = new Image
     button7 = new Image
     button8 = new Image
     button9 = new Image
     button10 = new Image
     button11 = new Image
     button12 = new Image


     button1.src = 'images/home_on.png'
     button2.src = 'images/home_off.png'
     button3.src = 'images/services_on.png'
     button4.src = 'images/services_off.png'
     button5.src = 'images/about_on.png'
     button6.src = 'images/about_off.png'
     button7.src = 'images/contact_on.png'
     button8.src = 'images/contact_off.png'
     button9.src = 'images/links_on.png'
     button10.src = 'images/links_off.png'
     button11.src = 'images/news_on.png'
     button12.src = 'images/news_off.png'

 }