Question

i am making simple autosuggestion (autocompleter) plugin with jQuery. Unfortunately i have to use jsonp. It is ok and it works, but when i am aborting request it will throw error.

Uncaught TypeError: Property 'jQuery171036404498340561986_1330693563756' of object [object Window] is not a function

There is code

if(xhr) {xhr.abort()};
xhr = $.ajax({
    url: "someurl/getmedata",
    type: 'get',
    dataType: 'jsonp',
    data: {q: "query"},
    success: function(results) {},
    error: function() {}
})

Classic way with json, xml or other request works fine.

Anny suggestion?

Answer 1

JSONP does not use XMLHTTPRequest but actually creates a <script> tag within the document to be able to make the cross-domain requests.

You simply cannot abort JSONP requests.

It is stated in the $.ajax() documentation:

Some types of Ajax requests, such as JSONP and cross-domain GET requests, do not use XHR; in those cases the XMLHttpRequest and textStatus parameters passed to the callback are undefined.

As for jQuery 1.5+, previously was returning the XHR object from $.ajax(), now it returns a superset jqXHR object which encapsulates the XHR object.

When the transport mechanism is something other than XMLHttpRequest (for example, a script tag for a JSONP request) the jqXHR object simulates native XHR functionality where possible.

So it returns an object but some functionnalities are actually not available, like .abort().

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The plugin jQuery-JSONP seems to offer the possibility to manually abort JSONP requests. I haven’t used it myself but it’s worth giving it a try.