anchor.diff:  
           var newDate = ev.newSelection[0];
           var date = dtdate.format(newDate);
  -        var day = date.slice(8, 10);
  +        var day = date.slice(-2);
           var day_id = "#" + day;
  -        if (day[0] === "0") {
  -          var day_selector = "_" + day[1];
  -        } else {
  -          var day_selector = "_" + day;
  -        };
  -        if ($("a:contains('Logout')").attr("href").length === 11) {
  -          var user_id = $("a:contains('Logout')").attr("href").slice(-1)
  -        } else {
  -          var user_id = $("a:contains('Logout')").attr("href").slice(-2)
  -        }
  -        if ($("td[id$='" + day_selector + "']:not(.yui3-calendar-column-hidden)").hasClass("available")) {
  -          $("td[id$='" + day_selector + "']:not(.yui3-calendar-column-hidden)").removeClass("available").css("background-color", "white");
  -          var request = $.ajax({
  -            url: "/users/" + user_id + "/availabilities/" + $(day_id).text(),
  -            type: "DELETE"
  -          });
  -        } else {
  -          $("td[id$='" + day_selector + "']:not(.yui3-calendar-column-hidden)").addClass("available").css("background-color", "#14A714");
  -          var request = $.ajax({
  -            url: "/users/" + user_id + "/availabilities",
  -            type: "POST",
  -            data: { date: date}
  -          });
  -          request.done(function(response) {
  -            if (response["id"]) {
  -              $("#available").append("<p id= " + response['day'] + " class='id_for_me'>" + response['id'] + "</p>");
  -            }
  -          })
  -        }
  -        Y.one("#selecteddate").setHTML(dtdate.format(newDate));
  +        var day_selector = +day; // convert possible leading-zero, single-digit to integer (+"01" = 1)
  +
  +        var selected_day_node = $("td[id$='_" + day_selector + "']:not(.yui3-calendar-column-hidden):not(.booked)");
  +        $.each(selected_day_node, function(index, node){
  +          var user_id = currentUserId();
  +          node = $(node);
  +          if (node.hasClass("available")) {
  +            node.removeClass("available").css("background-color", "white");
  +            var request = $.ajax({
  +              url: "/users/" + user_id + "/availabilities/" + $(day_id).text(),
  +              type: "DELETE"
  +            });
  +          } else {
  +            node.addClass("available").css("background-color", "#14A714");
  +            var request = $.ajax({
  +              url: "/users/" + user_id + "/availabilities",
  +              type: "POST",
  +              data: { date: date}
  +            });
  +            request.done(function(response) {
  +              if (response["id"]) {
  +                $("#available").append("<p id= " + response['day'] + " class='id_for_me'>" + response['id'] + "</p>");
  +              }
  +            });
  +          }
  +        });
         });
       });
     });
  
positive.code:         <!-- this passes the host_id aka user_id as a pairing_id, please do not panic it's ok. -->
        <% end %>
      </ul>
  
    </div>
  
    <div id="user_availabilities" class="displays">
      <h1>Availabilities</h1>
      <div id="available">
      <% @user.availabilities.each do |availability| %>
        <p id="<%= availability.date.last(2) %>" class="id_for_me"><%= availability.id %></p>
      <% end %>
      </div>
      <br>
      <div id="demo" class="yui3-skin-sam yui3-g"> <!-- You need this skin class -->
  
  
negative.code:        </div>
        </div>
      </div>
  </div>
  
  