if (document.images) {
     button1 = new Image
     button2 = new Image
     button3 = new Image
     button4 = new Image

     button1.src = '../images/btn_customer_reviews_.gif'
     button2.src = '../images/btn_customer_reviews_o.gif'
     button3.src = '../images/btn_write_review.gif'
     button4.src = '../images/btn_write_review_o.gif'
 }