在表单提交上更新KnockoutJS数组

Question

希望通过在用户点击提交按钮时更新KO数组来改善用户体验，而不是像Knockout那样自动完成。把这个测试页放在Fiddle上 - http://jsfiddle.net/HaSNd/ - 但是需要一个神奇的触摸......

JS：

function ViewModel() {

    var self = this;

    self.someVal = ko.observable();

    self.items = ko.observableArray([{
        someVal: "first item"
    }]);

    self.submitForm = function () {
        self.items.push({
            someVal: self.someVal()
        });
    };

    self.updateItem = function () {
        //Magic here
    };
}

var vm = new ViewModel();
ko.applyBindings(vm);

HTML

<form data-bind="submit: submitForm">
    <fieldset>
        <p><b>Add items to array:</b>
        </p>
        <p>
            <input data-bind="value: someVal" type="text" />
        </p>
        <p>
            <button type="submit" data-bind="">Add item</button>
        </p>
    </fieldset>
</form>
<br />
<fieldset style="background-color: #eee; "> <b>Array summary:</b>
    <br />
    <ul data-bind="foreach: items">
        <li data-bind="text: someVal"></li>
    </ul>
</fieldset>
<p><b>Update items in array manually:</b>
</p>
<form data-bind="submit: updateItem, foreach: items">
    <fieldset>
        <p>
            <input data-bind="value: someVal" />
        </p>
        <button type="submit" data-bind="">Update item</button> <button type="submit" data-bind="">Cancel</button>
    </fieldset>
    <br />
</form>
<br />
<br />
<span data-bind="text: ko.toJSON($root)"></span>