#define DAC_CH1 25
string slider_value = "0";
const char* input_parameter = "value";
AsyncWebServer server(80);
....web-server part is all the same....
String processor(const String& var){
 if (var == "SLIDERVALUE"){
 return slider_value;
 }
 return String();
}
void setup(){
 Serial.begin(115200);
 dacWrite(DAC_CH1, slider_value);
 Serial.println("DAC Value 0");
 WiFi.begin(ssid, password);
 while (WiFi.status() != WL_CONNECTED) {
 delay(1000);
 Serial.println("Connecting...");
 }
 Serial.println(WiFi.localIP());
 server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
 request->send_P(200, "text/html", index_html, processor);
 });
 server.on("/slider", HTTP_GET, [] (AsyncWebServerRequest *request) {
 String message;
 if (request->hasParam(input_parameter)) {
 message = request->getParam(input_parameter)->value();
 slider_value = message;
 ledcWrite(DAC_CH1, slider_value.toInt());
 }
 else {
 message = "No message sent";
 }
 Serial.println(message);
 request->send(200, "text/plain", "OK");
 });
 server.begin();
}
 void loop() {}