Which two actions will achieve this goal?

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.

View Answer

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/