if (document.images) {
		tab_skilled_on = new Image;
		tab_skilled_on.src = "global/images/navigation/tab_1_skilled_on.gif";
		tab_business_on = new Image;
		tab_business_on.src = "global/images/navigation/tab_2_business_on.gif";
		tab_partner_on = new Image;
		tab_partner_on.src = "global/images/navigation/tab_3_partner_on.gif";
		tab_parent_on = new Image;
		tab_parent_on.src = "global/images/navigation/tab_4_parent_on.gif";
		tab_retirement_on = new Image;
		tab_retirement_on.src = "global/images/navigation/tab_5_retirement_on.gif";
		tab_student_on = new Image;
		tab_student_on.src = "global/images/navigation/tab_6_student_on.gif";
		tab_visitor_on = new Image;
		tab_visitor_on.src = "global/images/navigation/tab_7_visitor_on.gif";
		tab_working_on = new Image;
		tab_working_on.src = "global/images/navigation/tab_8_working_on.gif";
		tab_457_on = new Image;
		tab_457_on.src = "global/images/navigation/tab_5_457_on.gif";

		tab_skilled_off = new Image;
		tab_skilled_off.src = "global/images/navigation/tab_1_skilled_off.gif";
		tab_business_off = new Image;
		tab_business_off.src = "global/images/navigation/tab_2_business_off.gif";
		tab_partner_off = new Image;
		tab_partner_off.src = "global/images/navigation/tab_3_partner_off.gif";
		tab_parent_off = new Image;
		tab_parent_off.src = "global/images/navigation/tab_4_parent_off.gif";
		tab_retirement_off = new Image;
		tab_retirement_off.src = "global/images/navigation/tab_5_retirement_off.gif";
		tab_student_off = new Image;
		tab_student_off.src = "global/images/navigation/tab_6_student_off.gif";
		tab_visitor_off = new Image;
		tab_visitor_off.src = "global/images/navigation/tab_7_visitor_off.gif";
		tab_working_off = new Image;
		tab_working_off.src = "global/images/navigation/tab_8_working_off.gif";
		tab_457_off = new Image;
		tab_457_off.src = "global/images/navigation/tab_5_457_off.gif";
	}
	function button_on(imgname) {
		if (document.images) {
			document[imgname].src = eval(imgname + "_on.src");
		} 
	}
	function button_off(imgname) {
	   if (document.images) {
			document[imgname].src = eval(imgname + "_off.src");
		}
	}