SWT Browser when is executed JavaScript "successful"?

Question

I was wondering - when calling the org.eclipse.swt.browser.Browser method execute,

• How is the return boolean determined?
• When is the javaScript execution considered "successful"?
• In particular, what happens when I start some asynchronous function and wait for the response?
• Will the browser wait for the callback?
• Is success based on an empty call stack and no errors?

Thanks in advance!

edit:
I just checked: the browser does not wait for callbacks to be called

Answer 1

As far as I can tell from digging in the source code, the result will be decided by either of the following methods:

• Firefox: JS_EvaluateScriptForPrincipals

  If the script compiles and executes successfully, *rval receives the value from the last-executed expression statement processed in the script, and JS_EvaluateScriptForPrincipals or JS_EvaluateUCScriptForPrincipals returns JS_TRUE. Otherwise it returns JS_FALSE, and the value left in *rval is undefined.

• WebKit: JSEvaluateScript

  The value that results from evaluating script, or NULL if an exception is thrown.

So it sounds like, if there's no error, true will be returned.

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As far as the async part of your question is concerned, the Browser will not wait for the execution of the async task. What you can do, however, is define a BrowserFunction (as shown in this example) and call that method from JavaScript when you're done with your async task.