if (document.images)
{
  pic1= new Image(72,41); 
  pic1.src="/images/header/home_on.png"; 

  pic2= new Image(71,41); 
  pic2.src="/images/header/tour_on.png"; 

  pic3= new Image(82,1); 
  pic3.src="/images/header/forum_on.png"; 
  
  pic4= new Image(70,41); 
  pic4.src="/images/header/blog_on.png"; 
  
  pic5= new Image(158,41); 
  pic5.src="/images/header/signup_on.png"; 
}