The XMLHttpRequest() version works but the fetch version does not.
The ESP receives the command, and returns the answer (Serial print for confirmation) but I dont get an answer by fetch.......
Thanks in advance.
If you use the Web Console in your browser, you can see the requests and response to each network call. This will tell you whether the response is coming back to the browser or not.
You can also change the code to log the response object itself and see the detail in the browser console:
fetch("HTTP://192.168.1.80/temperature")
.then(response => {
console.log(response);
return response.json();
})
.then(data => {alert('Success:', data[0])});