gridPowerDeltaValue in UI

index.html

@@ -144,6 +144,8 @@
 
 <button id="admin" onclick="toggleAdmin()">Admin</button>
 
+<div id="gridPowerDelta"></div>
+
 <script>
   let admin = false;
 
@@ -153,6 +155,7 @@
   }
 
   const title = document.getElementById("title");
+  const gridPowerDelta = document.getElementById("gridPowerDelta");
   const relayList = document.getElementById("relayList");
 
   function getUrl(path) {
@@ -241,6 +244,7 @@
         data = JSON.parse(r.response);
         dataAge = Date.now();
         title.innerText = data.wifi.hostname;
+        gridPowerDelta.innerText = "gridPowerDelta=" + data.gridPowerDeltaValue + "W";
         for (let index = 0; index < data.relays.length; index++) {
           const relayData = data.relays[index];
           const relayTag = document.getElementById("relay" + index) || create(index);

src/http.cpp

@@ -90,6 +90,9 @@ void httpStatus() {
   mqtt["host"] = getMqttHost();
   mqtt["port"] = getMqttPort();
 
+  json["gridPowerDeltaValue"] = gridPowerDeltaValue;
+  json["gridPowerDeltaAge"] = millis() - gridPowerDeltaMillis;
+
   const auto relays = json["relays"].to<JsonArray>();
   relay0.json(relays.add<JsonObject>());
 #ifdef Sonoff4ChPro