Edit in JSFiddle

ko.applyBindings({
    isShowData:ko.observable(false)
});

<div>
    <input type="checkbox" data-bind="checked: isShowData" />
    <div data-bind="if:isShowData">if</div>
    <div data-bind="ifnot: isShowData">ifnot</div>
    <div data-bind="visible: isShowData">visible</div>
</div>