I have tried to use importScripts to load a second JavaScript file into my web worker, but although no error occurred, it didn't work. I narrowed the problem down to this very simple situation:

In the main HTML file:

<script>

var w = new Worker(script1.js);

w.addEventListener(message, function(e){

    alert(e.data);

})

w.postMessage();

</script>

In script1.js:

self.addEventListener(message, function(e){

    var a = 5;

    importScripts(script2.js);

    self.postMessage(a);

})

In script2.js:

a = 6

I would like to see a dialog displaying 6, because a was changed from 5 to 6 by importing script2.js, but the dialog shows 5. What am I missing here?