function f_nav(fv_nav_id) {
	if (fv_nav_id != "nav1") {
		// Get all ul in nav container
 		var v_element_nav1 = document.getElementById("nav1")
		var v_element_array = v_element_nav1.getElementsByTagName('ul');
		// Reset All to hidden
		for (v_loop = 0 ; v_loop < v_element_array.length ; v_loop++) {
			// Hide
			v_element_array[v_loop].style.display = "none";
		}
		if (fv_nav_id != "") {
			// Check element exists
			if (document.getElementById(fv_nav_id) != null) {
				// Display current
				document.getElementById(fv_nav_id).style.display = "block";
			}
		}
	}
}