How to exactly work with the JSON Object and jQuery, adding info to posts
I don't think that I can give reasons why this is better (i.e. faster).  Only I feel that it is more readable and scalable.

I like to use the data attributes for information like ids.  For a long time, classes were the way to go but we had to deal with cluttered classes :(.  Data attributes keep things cleaner in my opinion–plus it makes it easier to have multiple counters on the page.

&lt;ul class="container"&gt;
  &lt;li class="counter" data-counter="60-x"&gt;x&lt;/li&gt;
  &lt;li class="counter" data-counter="60-y"&gt;y&lt;/li&gt;
  &lt;li class="counter" data-counter="60-z"&gt;z&lt;/li&gt;
&lt;/ul&gt;

&lt;ul class="container"&gt;
  &lt;li class="counter" data-counter="64-x"&gt;x&lt;/li&gt;
  &lt;li class="counter" data-counter="64-y"&gt;y&lt;/li&gt;
  &lt;li class="counter" data-counter="64-z"&gt;z&lt;/li&gt;
&lt;/ul&gt;


Using the same data:

var data = {
    "posts": {
        "60": { "x" : "100", "y" : "200" , "z" : "300" },
        "64": { "x" : "400", "y" : "500" , "z" : "560" }
    }
};


And then using javascripts for-in:

var posts = data.posts;

for(var item in posts) {
    for(var counter in posts[item]) {
        var selector = "[data-counter=" + item + "-" + counter + "]",
            count = posts[item][counter];

        $(selector).text(count);   
    }
}