A web worker is a JavaScript running in the background,
without affecting the performance of the page.
our HTML file create worker process ,which will run time consuming task
in background in
file bigLoop.js & return result by calling postMessage method
in Html file we get result passed by bigLoop.js in worker.onmessage in
event.data
HTML:
<html>
<head>
<title>Big for loop</title>
<script>
var worker = new Worker('bigLoop.js');
worker.onmessage = function (event) {
alert("Completed " + event.data + " iterations" );
worker.terminate()
};
function sayHello() {
alert("Hello sir...." );
}
</script>
</head>
<body>
<input type = "button" onclick = "sayHello();" value = "Say Hello"/>
</body>
</html>
BigLoop.js
for (var i = 0; i <= 1000000000; i += 1) {
var j = i;
}
postMessage(j);
When a web worker object is created, it will continue to listen for
messages (even after the external script is finished)
until it is terminated hence call terminate.
w.terminate();
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