
If the request is already complete, the callback is fired immediately. fail() callbacks on a single request, and even to assign these callbacks after the request may have completed. The Promise interface in jQuery 1.5 also allows jQuery's Ajax methods, including $.getJSON(), to chain multiple. For information about the arguments this function receives, see the jqXHR Object section of the $.ajax() documentation. The jqXHR.done() (for success), jqXHR.fail() (for error), and jqXHR.always() (for completion, whether success or error added in jQuery 1.6) methods take a function argument that is called when the request terminates. This jQuery XHR object, or "jqXHR," returned by $.getJSON() implements the Promise interface, giving it all the properties, methods, and behavior of a Promise (see Deferred object for more information).

The jqXHR ObjectĪs of jQuery 1.5, all of jQuery's Ajax methods return a superset of the XMLHTTPRequest object. python making POST request with JSON data Sending post request with both data and JSON parameters Python 3 - POST request with urllib.

See the discussion of the jsonp data type in $.ajax() for more details. If the URL includes the string "callback=?" (or similar, as defined by the server-side API), the request is treated as JSONP instead. For example, all strings represented in JSON, whether they are properties or values, must be enclosed in double-quotes.

JSON is a data-interchange format with syntax rules that are stricter than those of JavaScript's object literal notation. Avoid frequent hand-editing of JSON data for this reason. Important: As of jQuery 1.4, if the JSON file contains a syntax error, the request will usually fail silently.
