I'm using a Webforms page. On it I have a KnockoutJS ViewModel that gets a serialized JSON list of "Customers" by making a call to the backend C# code.

I data-bind that array to a combobox and I want to add the selected Customer to another array when a button is clicked. I want the list of selected customers to appear in a simple unordered list.

I'm not quite sure how add Customers to the "SelectedCustomers" property when clicking on the "Add" button. Note: I don't wan't move them, just copy.

**Javascript/Knockout Bindings**

```
<script type="text/javascript">
    $(document).ready(function() {

        function CustomerViewModel() {
            var self = this;

            self.Customers= <%= getJson() %>;
            self.SelectedCustomers = ko.observableArray([]);

            //operations
            self.addCustomerToList = function() {
                //Add selected customer to self.SelectedCustomers 
            }

        }

        ko.applyBindings(new CustomerViewModel());
    });
    </script>

```

**HTML elements**

```
<select data-bind="options: Customers, optionsText: 'CustomerName', value: CustomerID, optionsCaption: 'Select a Customer to Add'"></select>

<button type="submit">Add Customer</button>

Selected Customers:

<ul data-bind="foreach: SelectedCustomers">
 <li><span data-bind="text: CustomerName"></span></li>
</ul>

```