if (document.images)
    {
		preload_image_object = new Image();
      
		// set image url
		image_url = new Array();
		image_url[0] = "/images/nav_icon_selected.gif";
		image_url[1] = "/images/nav_sub_selected.gif";
		
		image_url[2] = "/images/nav_sectional_process1_sel.gif";
		image_url[3] = "/images/nav_sectional_process2_sel.gif";
		image_url[4] = "/images/nav_sectional_process3_sel.gif";
		image_url[5] = "/images/nav_sectional_process4_sel.gif";
		
		image_url[6] = "/images/nav_sectional_exp1_sel.gif";
		image_url[7] = "/images/nav_sectional_exp2_sel.gif";
		image_url[8] = "/images/nav_sectional_exp3_sel.gif";
		image_url[9] = "/images/nav_sectional_exp4_sel.gif";

		var i = 0;
		for(i=0; i<=9; i++) 
		preload_image_object.src = image_url[i];
    }