Tumblr multi-like

tumblr-multilike.js

(function() {

  // This handles having multiple like buttons of the same post on the page
  // at once. When you like/unlike one the others will update accordingly
  // I.E. One in a grid of posts and one in an overlay loaded via ajax on top of the grid.
  // See thingslog-theme.tumblr.com as an example.

  if (Tumblr && Tumblr.LikeButton) {
    Tumblr.LikeButton.update_like_state = function(data) {
      if (data.post_id) {
        var iframes = document.querySelectorAll("#like_iframe_" + data.post_id);
        for (var i = 0; i < iframes.length; i++) {
          iframes[i].contentWindow.postMessage("state_update;" + JSON.stringify(data), "http://assets.tumblr.com");
        }
      }
    };
  }

  if (Tumblr) {
    Tumblr.LikeButtonUpdate = (function() {
      return {
        post_message_event: function(action, a)  {
          var name   = action[0];
          var postID = action[1];
          var result = action[2];

          if (name === "tumblelog_like") {
            var buttons = document.querySelectorAll("#like_button_" + postID);
            for (var i = 0; i < buttons.length; i++) {
              buttons[i].classList[result === "liked" ? "add" : "remove"]("liked");
            }
          }
        }
      }
    }());
  }

})();