diff --git a/core/misc/date.js b/core/misc/date.js
index 3f401d5..fe2a239 100644
--- a/core/misc/date.js
+++ b/core/misc/date.js
@@ -1,37 +1,41 @@
+/**
+ * @file
+ * Polyfill for HTML5 date input.
+ */
+
 (function ($, Modernizr, Drupal) {
 
   "use strict";
 
   /**
    * Attach datepicker fallback on date elements.
+   *
+   * @type {Drupal~behavior}
+   *
+   * @prop {Drupal~behaviorAttach} attach
+   *   Attaches the behavior. Accepts in `settings.date` an object listing
+   *   elements to process, keyed by the HTML ID of the form element containing
+   *   the human-readable value. Each element is an datepicker settings object.
+   * @prop {Drupal~behaviorDetach} detach
+   *   Detach the behavior destroying datepickers on effected elements.
    */
   Drupal.behaviors.date = {
-    /**
-     * Attaches the behavior.
-     *
-     * @param settings.date
-     *   A list of elements to process, keyed by the HTML ID of the form element
-     *   containing the human-readable value. Each element is an datepicker
-     *   settings object.
-     */
     attach: function (context, settings) {
       var $context = $(context);
       // Skip if date are supported by the browser.
       if (Modernizr.inputtypes.date === true) {
         return;
       }
-      $context.find('input[data-drupal-date-format]').not('.hasDatepicker').each(function () {
+      $context.find('input[data-drupal-date-format]').once('datePicker').each(function () {
         var $input = $(this);
         var datepickerSettings = {};
-        var dateFormat;
-        dateFormat = $input.data('drupalDateFormat');
+        var dateFormat = $input.data('drupalDateFormat');
         // The date format is saved in PHP style, we need to convert to jQuery
         // datepicker.
-        dateFormat = dateFormat
+        datepickerSettings.dateFormat = dateFormat
           .replace('Y', 'yy')
           .replace('m', 'mm')
           .replace('d', 'dd');
-        datepickerSettings.dateFormat = dateFormat;
         // Add min and max date if set on the input.
         if ($input.attr('min')) {
           datepickerSettings.minDate = $input.attr('min');
@@ -42,12 +46,9 @@
         $input.datepicker(datepickerSettings);
       });
     },
-    /**
-     * Detach the behavior destroying datepickers on effected elements.
-     */
     detach: function (context, settings, trigger) {
       if (trigger === 'unload') {
-        $(context).find('input[data-drupal-date-format].hasDatepicker').datepicker("destroy");
+        $(context).find('input[data-drupal-date-format]').findOnce('datePicker').datepicker('destroy');
       }
     }
   };