luci/applications/luci-app-vpn-policy-routing/luasrc/view/vpn-policy-routing/js.htm

<script type="text/javascript">
//<![CDATA[
 function button_action(action) {
	var xhr = new XHR(false);
	var btn_start = document.getElementById("btn_start");
	var btn_action = document.getElementById("btn_action");
	var btn_stop = document.getElementById("btn_stop");
	var btn_enable = document.getElementById("btn_enable");
	var btn_disable = document.getElementById("btn_disable");
	var btn_spinner;
	switch (action.name) {
		case "start":
			btn_spinner = document.getElementById("btn_start_spinner");
			break;
		case "action":
			btn_spinner = document.getElementById("btn_action_spinner");
			break;
		case "stop":
			btn_spinner = document.getElementById("btn_stop_spinner");
			break;
		case "enable":
			btn_spinner = document.getElementById("btn_enable_spinner");
			break;
		case "disable":
			btn_spinner = document.getElementById("btn_disable_spinner");
			break;
	}
	btn_start.disabled = true;
	btn_action.disabled = true;
	btn_stop.disabled = true;
	btn_enable.disabled = true;
	btn_disable.disabled = true;
	spinner(btn_spinner, 1);
	xhr.get('<%=luci.dispatcher.build_url("admin", "vpn", "vpn-policy-routing", "action")%>/' + action.name, null,
		function (x) {
			if (!x) {
				return;
			}
			btn_start.disabled = false;
			btn_action.disabled = false;
			btn_stop.disabled = false;
			btn_enable.disabled = false;
			btn_disable.disabled = false;
			spinner(btn_spinner, 0);
			location.reload();
		 });
}
function spinner(element, state) {
	if (state === 1) {
		element.style.width = "16px";
		element.innerHTML = '<img src="<%=resource%>/icons/loading.gif" alt="<%:Loading%>" width="16" height="16" style="vertical-align:middle" />';
	}
	else {
		element.style.width = "0px";
		element.innerHTML = '';
	}
}
//]]>
</script>