You are developing a web application that consumes services from a third-party application. A web worker processes the third-party application requests in the background. A page in the application instantiates the web worker process.
You need to establish two-way communications between the web worker process and the page.
Which two actions will achieve this goal? (Each correct answer presents a complete solution. Choose two.)
A . From the web worker, use the onconnect event handler of the main page to capture events.
B . From the main page, use the onmessage event handler of the web worker to capture events.
C . From the web worker, use the onmessage event handler of the main page to capture events.
D . From the main page, use the onconnect event handler of the web worker to capture events.
Answer: B, C
Explanation:
* When postMessage() is called from the main page, our worker handles that message by defining an onmessage handler for the message event.
* Server-Sent Events – One Way Messaging
A server-sent event is when a web page automatically gets updates from a server.
Receive Server-Sent Event Notifications
The EventSource object is used to receive server-sent event notifications:
Example
var source = new EventSource("demo_sse.php");
source.onmessage = function(event) {
document.getElementById("result").innerHTML += event.data + "<br>";
};
Reference:
http://www.w3schools.com/html/html5_serversentevents.asp
http://www.html5rocks.com/en/tutorials/workers/basics/