javascript - Uncaught ReferenceError: importScripts is not defined

Question

Why do I keep getting this error?

I should be able to use this global function right?

http://www.html5rocks.com/en/tutorials/workers/basics/

I'm using chrome.

I'm using https://code.google.com/p/bitjs/ and it begins with

importScripts('io.js');
importScripts('archive.js');

Answer 1

When you create a worker it is actually executed twice. The first pass is in the context of the global 'window' object(meaning you have access to all the window object functions). The second call through is in the context of the worker which has a different global object, one where 'importScripts' exists.

// proper initialization
if( 'function' === typeof importScripts) {
   importScripts('script2.js');
   addEventListener('message', onMessage);

   function onMessage(e) { 
     // do some work here 
   }    
}

Notice the addEventListener is inside the if statement. If you place it outside of it, your callback will be registered twice. Once on the 'window' global and once on the worker's global.

Happy coding!