Data creates new object

[holdenru@…]

​http://jsfiddle.net/holden321/Pruj2/

var a={};
$(document).data(a);
console.log(a==$(document).data()); // returns false, expected: true, BUG?!

var a={};
$(document).data({a:a});
console.log(a==$(document).data('a')); // returns true, expected: true, OK

[scottgonzalez]

There is no API for setting the entirety of the data. You're using an API for setting multiple individual properties, of which you're setting none.