<p>Provides a JSONPRequest class for repeated JSONP calls, and a convenience method Y.jsonp(url, callback) to instantiate and send a JSONP request.</p>

<p>Both the constructor as well as the convenience function take two parameters: a url string and a callback.</p>

<p>The url provided must include the placeholder string "{callback}" which will be replaced by a dynamically generated routing function to pass the data to your callback function. An example url might look like "http://example.com/service?callback={callback}".</p>

<p>The second parameter can be a callback function that accepts the JSON payload as its argument, or a configuration object supporting the keys:</p> <ul> <li>on - map of callback subscribers <ul> <li>success - function handler for successful transmission</li> <li>failure - function handler for failed transmission</li> <li>timeout - function handler for transactions that timeout</li> </ul> </li> <li>format - override function for inserting the proxy name in the url</li> <li>timeout - the number of milliseconds to wait before giving up</li> <li>context - becomes <code>this</code> in the callbacks</li> <li>args - array of subsequent parameters to pass to the callbacks</li> <li>allowCache - use the same proxy name for all requests? (boolean)</li> </ul>