# WEB Worker DEMO
* Requirement: a web server, here we use python to run a simple web server
```bash
python.exe -m SimpleHTTPServer 8080
#For python3, use this command:
python3 -m http.server 8080
```
* The HTML, master code
```xml
WEB Workder DEMO
```
* The JS, worker code
```javascript
var runningTimer;
//await must in async function;
async function report() {
//const d = new Date();
var strPost = "Fail to get time from server";
const timeServer = "http://worldtimeapi.org/api/timezone/Asia/Shanghai";
let response = await fetch(timeServer);
if (response.ok) {
let json = await response.json();
strPost=json.datetime;
}
this.postMessage(strPost);
}
this.addEventListener("message", function (event) {
let cmd = event.data;
switch (cmd) {
case "START":
this.postMessage("Started");
clearInterval(runningTimer);
runningTimer = setInterval(report, 1000);
break;
case "STOP":
this.postMessage("Stopped");
clearInterval(runningTimer);
break;
}
}, false);
```