Twitter Bootstrap手风琴功能

Question

Working with Bootstrap and JavaScript and I am using it as an accordion format - once clicked on the collapsed div it will open and show the items within the div based on the id.

Problem:

If the div doesn't contain any items i want it to open and show a message to the user:

"no items here" 

How do I go about doing that? In the JavaScript ?

This is what I have:

View

<div class="accordion-body collapse state-loading" data-group-id="13" data-bind="attr: { 'id': 'GroupMember_' + Id(), 'data-type-id': ModelId() }" id="GroupMember_15" data-type-id="15">
      <div class="accordion-inner no_border" data-bind="foreach: Children"></div><!--END: accordion-inner--></div>
</div>

If the Children are 0 i want it to open and have this text show: No items here

Javascript:

OnSuccess: function (data) {
                var _groups = linq.From(options.groupData);    
                var _groupsToUpdate = _groups .Where(function (x) { return x.Id == options.groupId; });
                if (_groupsToUpdate.Any()) {
                    _groupsToUpdate.First().Children = data.Items;                  
                }

Not sure if i am missing anything else to share - let me know.

UPDATE

Div Layout:

<div class='accordion-group'>
     <div class='accordion-heading'> Group 1 </div>
     <div class='accordion-body'>
          <div class='accordion-inner'> 
              <div class='element'>No items here</div> 
          </div>
     </div>
</div>

I have to click on the 'accordion-heading' class in order to display the 'accordion-body' and get into the accordion-inner items

Answer 1

You'd need to bind to the show event on the accordion elements and perform your check there, from your classes I'm assuming your using Bootstrap v2.3.2:

$('.accordion .collapse').on('show', function () {
    var $inner = $(this).find('.accordion-inner');
    if($inner.is(':empty')){
        $inner.html('No items here');
    }   
});

Demo fiddle

Note that the :empty selector is very picky, it will not work if there's any white space between the opening and closing tags of .accordion-inner .

You may also use if(!$.trim($inner.html())) to check if the element is empty or as @JL suggested check the length of the children elements just beware that text nodes are not treated like children, so a div with only text would be considered empty

Answer 2

Do you have jQuery installed? You can check if a <div> has children like this:

if ($('#divId').children().length == 0) {
     $('#divId').append("no items here");
}

If you don't have jQuery:

if (!document.getElementById('divId').hasChildNodes()) {
    document.getElementById('divId').innerHTML = "no items here";
}

Based on your edit, I think we're inspecting accordian-inner for children. If so, give it an ID and substitute that into our code. Note: You don't need a <div> to contain our "no items" message...the message will get printed with javascript (Plus, if you have a <div> there, then you've in effect added a child and the message no longer applies). Change your HTML to this:

<div class='accordion-group'>
     <div class='accordion-heading'> Group 1 </div>
     <div class='accordion-body'>
          <div id='innerId' class='accordion-inner'> 
              <!-- Remove the 'element' div -->
          </div>
     </div>
</div>

Then:

if (!document.getElementById('innerId').hasChildNodes()) {
    document.getElementById('innerId').innerHTML = "no items here";
}