if (document.images) {
	
	nav_home				= new Image();
	nav_home.src			= "source/nav_home.jpg";
	
	nav_home_on				= new Image();
	nav_home_on.src			= "source/nav_home_on.jpg";
	
	nav_sa					= new Image();
	nav_sa.src				= "source/nav_sa.jpg";
	
	nav_sa_on					= new Image();
	nav_sa_on.src			= "source/nav_sa_on.jpg";
	
	nav_ir					= new Image();
	nav_ir.src				= "source/nav_ir.jpg";
	
	nav_ir_on				= new Image();
	nav_ir_on.src			= "source/nav_ir_on.jpg";
	
	nav_os					= new Image();
	nav_os.src				= "source/nav_os.jpg";
	
	nav_os_on				= new Image();
	nav_os_on.src			= "source/nav_os_on.jpg";
	
	nav_ot					= new Image();
	nav_ot.src				= "source/nav_ot.jpg";
	
	nav_ot_on				= new Image();
	nav_ot_on.src			= "source/nav_ot_on.jpg";
	
	nav_oc					= new Image();
	nav_oc.src				= "source/nav_oc.jpg";
	
	nav_oc_on				= new Image();
	nav_oc_on.src			= "source/nav_oc_on.jpg";
	
	nav_news				= new Image();
	nav_news.src			= "source/nav_news.jpg";
	
	nav_news_on				= new Image();
	nav_news_on.src			= "source/nav_news_on.jpg";

	nav_contact				= new Image();
	nav_contact.src			= "source/nav_contact.jpg";
	
	nav_contact_on			= new Image();
	nav_contact_on.src		= "source/nav_contact_on.jpg";
	
}

function rollover(image_name, roll) {
	if (document.images) {
	  document[image_name].src = eval( roll + ".src" );
	}
}