knockoutjs not binding checked

knockoutjs not binding checked to array ie9

by ozzymcduff

HTML

<script src="http://ajax.aspnetcdn.com/ajax/knockout/knockout-2.1.0.debug.js"></script>
<div data-bind="foreach:vals, click:function(){
return true; }">
       <input type="checkbox" data-bind="attr:{value:$data}, checked: $parent.myArray" />
    <span data-bind="text:$data" ></span><br/>
</div>

JavaScript

$(function () {
        var viewModel = {
            myArray: ko.observableArray([]),
            vals:[1,2]
        }
        ko.applyBindings(viewModel);
});