Is there a way to implement a simple Heart vote(just +1 vote with counter without ability to vote more than once) using only Javascript / jQuery and HTML5 data attributes, other HTML5 APIs, without any serverside stuff?
You can use localStorage
to record that client has voted. Something like this:
localStorage.setItem('voted', true);
To check if client voted before:
var voted = localStorage.get item('voted');
Update:
As you need a counter, you may try one of BAAS (backend-as-a-service) services, such as parse.com or kinvey.com