I've tested it in Firefox 3.x, Chrome 1.x, IE7, Opera 9.x, Safari 3.x. All windows versions. It uses an iframe instead of a simple script tag (wich brings a separate window context, hence the added flexibility in callback naming and the possibility to detect faulty requests). I'm pretty confident it's generic enough to work in all browsers supported by jQuery (maybe with some tweaks here and there because declaring variables in the iframe window's context must be done at the proper stage in the iframe's lifecycle -- I managed to find a common ground for the browsers I tested the plugin in but let me tell you I battled to find it). I know I could have made things simpler by exposing callback functions as fields of an object in the main window's context ($.jsonp.callbacks for instance) but then I would have lost the benefit of the same callback name for every call. "Being able to specify a fixed jsonp callback function seems useful too and probably not hard to add."
With a script tag in the main window's head, it's almost impossible unless you have a global data structure to reroute responses and a callback function code generator or expect the user to filter what response corresponds to what request in his own callbacks. Keep in mind you may have several requests running with the same callback name at once and you don't know in which order they'll complete. It seems strange to me you seem to find this callback naming thing so secondary. I can assure you that the features the plugin provides in that department are as valuable as getting an error callback properly notified. Anyway, the source is MIT and for good reason ;) so don't hesitate to pillage it as you see fit. All variables are one-letter for size purpose but it 's heavily commented and should be easy to follow. Now on the topic of having $.ajax() being a catch-all method for every protocol on the planet, I'm not sure I buy it. I was browsing through $.ajax() source code and I was quite puzzled at the number of conditionals and tricks packed in a single function. I was almost surprised not to see an image preloading subcase in there ;) I mean, JSONP is not AJAX, unfortunately mainly due to technical differencies. For instance: - the dataFilter callback will never receive text simply because the browser never has access to it in the first place, so you end up passing the resulting JSON object to it, - you cannot pass an xhr object to the callbacks because there's none hence my use in $.jsonp() of an object containing the request's options and an abort method. Imagine the clarity of the documentation regarding said callbacks if you had to implement that into $.ajax() (not to mention how bloated the code would get) - you never, ever have access to HTTP headers (which would be incredibly nice btw) >From a practical point of view, I guess most people will use $.getJSON so that they don't have to deal with the intricaties of $.ajax() options setting. That's in this spirit that I created $.json() (which has far less options). It seemed the easier, safer and cleaner way to go. As a side note, I'm not sure I like the idea of setting defaults through $.ajaxSetup() that will be applied to XML, text, JSON, JSONP and whatever new data format / protocol either. Don't get me wrong, I have a $.json.setup method myself and I know there's a need but it seems to "all or nothing" to me. I've just finished an add-on to $.jsonp() that will allow to make "prepared" requests (a bit like SQL prepared statements). The idea is basically to create pre-made functions that actually call $.jsonp() but with default options (and a url templating engine and a nice arguments to request data mapper). Interestingly, the technique can be applied to $.ajax() and the add-on installs the hook for it too. All it needs right now is documentation (I hate to release without at least an API doc and some examples). Hell, here is an example taken from my test file of how it works, I can't resist: // Creating the prepared request var getYouTubeUser = $.jsonp.prepared( // url template "http://gdata.youtube.com/feeds/api/users/{user}?callback=?";, // generated function parameters // undefined: no default value, optional parameter // null: no default value, mandatory parameter { "user": null, }, // default parameters for the request { "data": { "alt": "json-in-script" }, "dataFilter": dataFilter } ); // Using the function getYouTubeUser("julianaubourg")({ "success": function(json) { // success code }, "error": function(d,msg) { // error code } }); In conclusion, well, I think json support in $.ajax() as of today is enough for what most people will attempt with it (that is pretty simple and borded requests). I really think $.jsonp is more oriented toward advanced uses (I made it because I'm working on a heavily service-consuming website at the moment and thought some people would need something more advanced like I did). Oh yeah, and from a performance point of view, using iframes instead of script tags is much more time consuming. Empirical tests I made showed that sending a jsonp request to a local webserver (static text) using $.jsonp() is about 2x to 10x slower than the $.ajax() method (Safari being the fastest and Firefox the slowest). I blame it on the insane chrome activity that is performed by most browsers when you have an iframe loading. Of course, it's still a fraction of the time a normal request over the network will take but it still has to be taken in consideration. Regards, -- Julian 2009/3/14 Dave Methvin <[email protected]> > > > To summarize, $.jsonp() is ... an entirely new function which provides > > the same options as $.ajax() does (as long as said options are relevant > > to a jsonp request). > > Yeah, that's what $.ajax is trying to do with jsonp as well. At the > moment I think there are some issues with jsonp through $.ajax, a > combination of documentation problems and missing features that could > be implemented for consistency with other $.ajax requests. > > On the error callback, does that solution work in all browsers? If so, > it sounds like $.ajax should implement it for jsonp. Being able to > specify a fixed jsonp callback function seems useful too and probably > not hard to add. > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jQuery Development" group. 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