Little drop in example, Out of the top of my head but should work

gistfile1.js

//Any element with a class of voteBtn will trigger this, it can ba a button, a <a>, a <div> you name it
//As long as it has the data attribute
$('.voteBtn').click(function(e){
  
  var $that = $(this);
  $.post('/url/where/data/is/sendTo.php', {category_id: $that.data('category-id')}, function(data){
    if (data.result){ //data needs to be valid json:  {result: true}
      $that.text("Voted!").attr('disabled', 'disabled');
    } else {
      $that.text("Try again later, something broke").attr('disabled', 'disabled');
      setTimeout(function(){ $that.removeAttr('disabled') }, 2000);
    }
    
  });
  
  //Don't do what ever it is that you normally do
  e.preventDefault();
  //DON'T RETURN FALSE. THAT'S DEPECRATED WEB 2 SHIT
});