Question

In my page, I have a combo box with an add button. How do I create a new combo box below the original combo box when I clicked the add button? If clicked again, it will produce another combo box. The value inside each combo box is called from the database.

Answer 1

Here’s an example, though you’ll have to work out the middle tier and back end portion yourself.

Example: http://jsfiddle.net/9hvbt/3/

JavaScript

$('#btnAdd').click(function(){
    //Use Ajax to talk to your server (middle tier)
    $.ajax({
        url: '/echo/json/', //Replace with your URL to return Database data (JSON format)
        dataType: 'json', 
        type: 'get', 
        success: function(data){
            //Use the returned data to pass into CreateDropDown (Hard coded for an example)
            CreateDropDown(["Item 1", "Item 2", "Item 3"]); 
        }
    });
}); 

function CreateDropDown(data){
    var $newSelect = $('<select />'); 
    $.each(data, function(i, val){
        $newSelect.append($('<option />', {
            'text':val
        }));            
    });  
    $newSelect.appendTo('#dropDowns'); 
}

​
​
HTML

<div id='dropDowns'>
    <select>
    <option>Item 1</option>
    <option>Item 2</option>
    <option>Item 3</option>
    </select>
</div>
<input type='button' id='btnAdd' value="Add" />​

EDIT

You should also read up on jQuery’s AJAX method