How can I make XHR.onreadystatechange return its result?

Question

I\'m new to JavaScript programming. I\'m now working on my Google Chrome Extension. This is the code that doesn\'t work... :P

I want getURLInfo function

Answer 1

You can't do it at all for asynchronous XHR calls. You cannot make JavaScript "wait" for the HTTP response from the server; all you can do is hand the runtime system a function to call (your handler), and it will call it. However, that call will come a long time after the code that set up the XHR has finished.

All is not lost, however, as that handler function can do anything. Whatever it is that you wanted to do with a return value you can do inside the handler (or from other functions called from inside the handler).

Thus in your example, you'd change things like this:

    xhr.onreadystatechange = function()
    {
        if (xhr.readyState == 4)
        {
            var resp = JSON.parse(xhr.responseText);
            //
            // ... whatever you need to do with "resp" ...
            //
        }
    }
}