modify collapse plugin to work with select = selected

Issue

I am trying to use a <select> so that on change it hide/shows a div.

I want to make use of the twitter bootstrap collapse plugin.

I have it half working with this example http://plnkr.co/edit/9lPe61?p=preview

But when you add selected to the select it breaks everything: http://plnkr.co/edit/w9XW8R?p=preview

<div class="accordion" id="accordion" >
    <div class="accordion-group">
      <select class="accordion-toggle">
         <option value="1" data-toggle="collapse" data-parent="#accordion" data-target="#collapseOne">1</option>
         <option value="2" data-toggle="collapse" data-parent="#accordion" data-target="#collapseTwo">2</option>
         <option value="3" data-toggle="collapse" data-parent="#accordion" data-target="#collapseThree">3</option>
      </select>

      <div id="collapseOne" class=" collapse in">
        <div class="accordion-inner">
          Anim1 pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
        </div>
      </div>
    </div>
    <div class="accordion-group">
      <div id="collapseTwo" class=" collapse">
        <div class="accordion-inner">
          Anim2 pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
        </div>
      </div>
    </div>
    <div class="accordion-group">
      <div id="collapseThree" class=" collapse">
        <div class="accordion-inner">
          Anim3 pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS.
        </div>
      </div>
    </div>
</div>

JS - I guess I would need to add to the plugin to check if there is a selected="selected" so that it works with selects also, but I cant figure out where abouts this needs to go?

/* =============================================================
 * bootstrap-collapse.js v2.3.1
 * http://twitter.github.com/bootstrap/javascript.html#collapse
 * =============================================================
 * Copyright 2012 Twitter, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============================================================ */


!function ($) {

  "use strict"; // jshint ;_;


 /* COLLAPSE PUBLIC CLASS DEFINITION
  * ================================ */

  var Collapse = function (element, options) {
    this.$element = $(element)
    this.options = $.extend({}, $.fn.collapse.defaults, options)

    if (this.options.parent) {
      this.$parent = $(this.options.parent)
    }

    this.options.toggle && this.toggle()
  }

  Collapse.prototype = {

    constructor: Collapse

  , dimension: function () {
      var hasWidth = this.$element.hasClass('width')
      return hasWidth ? 'width' : 'height'
    }

  , show: function () {
      var dimension
        , scroll
        , actives
        , hasData

      if (this.transitioning || this.$element.hasClass('in')) return

      dimension = this.dimension()
      scroll = $.camelCase(['scroll', dimension].join('-'))
      actives = this.$parent && this.$parent.find('> .accordion-group > .in')

      if (actives && actives.length) {
        hasData = actives.data('collapse')
        if (hasData && hasData.transitioning) return
        actives.collapse('hide')
        hasData || actives.data('collapse', null)
      }

      this.$element[dimension](0)
      this.transition('addClass', $.Event('show'), 'shown')
      $.support.transition && this.$element[dimension](this.$element[0][scroll])
    }

  , hide: function () {
      var dimension
      if (this.transitioning || !this.$element.hasClass('in')) return
      dimension = this.dimension()
      this.reset(this.$element[dimension]())
      this.transition('removeClass', $.Event('hide'), 'hidden')
      this.$element[dimension](0)
    }

  , reset: function (size) {
      var dimension = this.dimension()

      this.$element
        .removeClass('collapse')
        [dimension](size || 'auto')
        [0].offsetWidth

      this.$element[size !== null ? 'addClass' : 'removeClass']('collapse')

      return this
    }

  , transition: function (method, startEvent, completeEvent) {
      var that = this
        , complete = function () {
            if (startEvent.type == 'show') that.reset()
            that.transitioning = 0
            that.$element.trigger(completeEvent)
          }

      this.$element.trigger(startEvent)

      if (startEvent.isDefaultPrevented()) return

      this.transitioning = 1

      this.$element[method]('in')

      $.support.transition && this.$element.hasClass('collapse') ?
        this.$element.one($.support.transition.end, complete) :
        complete()
    }

  , toggle: function () {
      this[this.$element.hasClass('in') ? 'hide' : 'show']()
    }

  }


 /* COLLAPSE PLUGIN DEFINITION
  * ========================== */

  var old = $.fn.collapse

  $.fn.collapse = function (option) {
    return this.each(function () {
      var $this = $(this)
        , data = $this.data('collapse')
        , options = $.extend({}, $.fn.collapse.defaults, $this.data(), typeof option == 'object' && option)
      if (!data) $this.data('collapse', (data = new Collapse(this, options)))
      if (typeof option == 'string') data[option]()
    })
  }

  $.fn.collapse.defaults = {
    toggle: true
  }

  $.fn.collapse.Constructor = Collapse


 /* COLLAPSE NO CONFLICT
  * ==================== */

  $.fn.collapse.noConflict = function () {
    $.fn.collapse = old
    return this
  }


 /* COLLAPSE DATA-API
  * ================= */

  $(document).on('click.collapse.data-api', '[data-toggle=collapse]', function (e) {
    var $this = $(this), href
      , target = $this.attr('data-target')
        || e.preventDefault()
        || (href = $this.attr('href')) && href.replace(/.*(?=#[^\s]+$)/, '') //strip for ie7
      , option = $(target).data('collapse') ? 'toggle' : $this.data()
    $this[$(target).hasClass('in') ? 'addClass' : 'removeClass']('collapsed')
    $(target).collapse(option)
  })

}(window.jQuery);

http://plnkr.co/edit/w9XW8R?p=preview

Solution

OP,

I think this http://plnkr.co/edit/qfB8Uf?p=preview is what you're after.

---

The important bits

JS

...
  $('document').ready(function () {
      $(".accordion-dropdpwn").on('change', function (e) {
          var selected_value = $(this).val(),
          $target_elem = $('a[href="' + selected_value + '"]');
          $target_elem.trigger('click');
      });

      $('.accordion-toggle').on('click', function () {
          var selected_value = $(this).attr('href');
          $(".accordion-dropdown option").removeAttr('selected');
          $('option[value="' + selected_value + '"]').attr('selected', 'selected');
      });

      $(".accordion-dropdown").trigger('change');
  });

...

Brief

Since the change event for the <select> returns the value of the selected option (child), I stuffed a reference to the accordion <a> that should be affected when the user changes the drop-down.

Once we have our reference, we simply trigger a click event on that item. The other important bit is making sure that when the page is loaded, the accordion will reflect the current state of the select — that is, whichever option has selected="selected" will be open/active.

Lastly, there is bi-directional control. Since if the user changes the <select>, the accordion changes, it's expected that clicking the accordion should change the <select>.

Hope this helps.

Answered By - couzzi