JSONP

gistfile1.js

function getJSONP( url, callback ) {

	var ud = 'json' + ( Math.random() * 100 ).toString().replace( /\./g, '' );

	window[ ud ]= function ( o ) { callback && callback( o ); };

	var script = document.createElement( 'script' );
	script.type = 'text/javascript';
	script.src = url.replace( 'callback=?','callback=' + ud );

	document.body.appendChild( script );

}