Comments on: jXHR: XHR API, JSON-P backend conduit

By: Merl

Merl — Thu, 07 Jul 2011 19:50:01 +0000

one problem for dynamic script loading is that you do not get XHR response.status from the server, so no way to check for 404 or 500. if you have an invalid url, you never get the publicAPI.onerror handler.

distinct from publicAPI.onerror, with HTML5 ( http://bit.ly/qb5GfU ; see item #14), you can define scriptElem.onerror for any type of error loading the script.

i added this mod to your script to handle invalid url errors:

after handleScriptLoad

// MOD: added handleScriptFail()
function handleScriptFail() {
if (!script_loaded) {
ThrowError(“Script failed to load ["+script_url+"], most probably due to an invalid URL or server error.”)
}
}

inside send:

// P4 MOD: added onerror
scriptElem.onerror = function() {
handleScriptFail.call(scriptElem);
};

By: shadedecho

shadedecho — Thu, 17 Sep 2009 00:10:26 +0000

@stimpy77 — i think you’ve actually hit on exactly why I think that standardizing on the same API is important… so that it’s easy to swap in optional implementations depending on technical environment but without having to code more complex code that makes calls differently. When it’s the same (or nearly the same) API, it greatly simplifies that kind of usage. And that’s my goal, to provide more options for cross-domain Ajax, but without fragmenting the API into an unmanageable mess.

By: stimpy77

stimpy77 — Sat, 29 Aug 2009 20:24:16 +0000

I think this API would be interesting if its intent was to be a fallback API rather than a “similar syntax”. So if a browser supports the new standard, it uses that, but if it doesn’t, it uses JSONP, either way no manual toggling involved for the developer.

By: shadedecho

shadedecho — Thu, 20 Aug 2009 22:17:06 +0000

good catch, thank you @checkca. Will fix ASAP.

By: checkca

checkca — Thu, 20 Aug 2009 22:14:46 +0000

I love mullet !

BTW, it seems that “internal_callback” variable is global…

By: Jadet

Jadet — Thu, 20 Aug 2009 19:49:20 +0000

hehe awesome

By: shadedecho

shadedecho — Thu, 20 Aug 2009 19:13:41 +0000

BTW, in honor of Dion’s awesome picture to visualize my API, this project can now be located at:

http://mullet.xhr.me

http://mulletxhr.com

By: marlonbtx

marlonbtx — Thu, 20 Aug 2009 17:06:15 +0000

so you are not using an iframe! you use script tag

By: marlonbtx

marlonbtx — Thu, 20 Aug 2009 17:02:24 +0000

lol funny pic

By: shadedecho

shadedecho — Thu, 20 Aug 2009 13:52:13 +0000

The main point of jXHR, besides putting the familiar and well-known XHR API wrapper on top of dynamic-script-tag JSON-P calls, was to provide the “onerror” error detection handler functionality.

If you set “onerror” handler, and your JSON-P call fails for some reason, then you’ll be immediately notified, rather than needing to do your own timer detection, etc.

Also, jXHR is less than 700 bytes when minified and gzip’d, so it’s really small and easy to use just about anywhere, including bookmarklets, cross-domain widgets, etc.

By: shadedecho

shadedecho — Thu, 20 Aug 2009 13:39:33 +0000

For the record, that is NOT a picture of me. :) But funny picture nonetheless, Dion. :)