Mastering Web Application

Chapter 3

As soon as this script tag is attached to the DOM the browser will request the URL
specified in the src attribute. The response, upon arrival, will have a body following
a pattern like:

angular.callbacks._k ({"name":"World","salutation":"Hello","greeting":

"Hello World!"});

A JSONP response looks like a regular JavaScript function call and in fact this exactly
what it is. AngularJS generated the angular.callbacks._k function behind the
scenes. This function, when invoked, will trigger a success callback invocation. The
URL supplied to the $http.jsonp function call must contain the JSON_CALLBACK
request parameter. AngularJS will turn this string into a dynamically generated
function name.

JSONP callback names generated by AngularJS will have a form

of angular.callbacks._[variable]. Make sure that your

back-end can accept callback names containing dots.

JSONP limitations

JSONP is a smart and useful work-around for the same-origin policy restrictions but
it has several limitations. Firstly, we should only GET HTTP requests can be issued
using the JSONP technique. Error handling is also very problematic, since browsers
won't expose HTTP response status from the