在JQuery / Ajax中刷新后清除或重置下拉菜单的选项

Question

How can I clear the options of select box after refresh ... I have two select boxes and both of their values after refresh didn't clear or reset i am working in code igniter here is my code.

    <?php echo form_dropdown('cat_id', $records2, '#', 'class="cho" id="category"');?>


 <script type="text/javascript">// 
 $(document).ready(function(){       
    $('#category').change(function(){        
        $("#items > option").remove(); //it is not working
        var category_id = $('#category').val();  
        $.ajax({
            type: "POST",
            url: "testController/get_items/"+category_id,

            success: function(items)
            {
                $.each(items,function(item_id,item_name) 
                {
                    var opt = $('<option />'); 
                    opt.val(item_id);
                    opt.text(item_name);
                    $('#items').append(opt); 
                });
            }

        });

    });
});
// ]]>

Answer 1

try

 $("#items").empty();

empty() method will clear all html

API Reference http://api.jquery.com/empty

Answer 2

$('#items')
    .find('option')
    .remove()
    .end();

IE6

$('#items')
    .empty();

Answer 3

Instead of

$("#items > option").remove(); //it is not working

try this

$("#items).html("");

Here is simple jsFiddle for you

UPDATE:

You might also consider to build you options markup first and then replace it at once, rather then sequentially append items.

$("#category").change(function(){        
    var category_id = $("#category").val();  
    $.ajax({
        type: "POST",
        url: "testController/get_items/" + category_id,
        success: function(items)
        {
            var options = "";
            $.each(items, function(item_id, item_name) 
            {
                options += "<option value=\"" + item_id + "\">" + item_name + "</option>";
            });
            $("#items").html(options);
        }
    });
});

Answer 4

There is nothing in the document.ready event handler. Everything is contained within $('#category').change(function(){ meaning nothing will happen on page refresh.