Edit The initially suggested answer was if you want JSON string / object, which I inferred by the output string you had in the question. If you just want to get the key / value pair you can simply iterate data attribute collection.
Live Demo
$.each($('a').data(), function(i, v) {
alert('"' + i + '":"' + v + '",');
});
Initially suggested answer on supposition that you want JSON string / object
You can make key value pair object (json object) of data attributes by iterating through data attributes collection using data()
which will give the collection of data attributes. After making the json string we can make jSON object using $.parseJSON and using loop to get key / value pair from it.
Live Demo
strJson = "{"
$.each($('a').data(), function(i, v) {
strJson += '"' + i + '":"' + v + '",';
});
strJson = strJson.substring(0, strJson.length - 1);
strJson += '}';
var jsonObject = $.parseJSON( strJson );
for (var key in jsonObject)
alert(key + " : " + jsonObject[key]);