How to pre-select an option in a dropdown knockout js

http://stackoverflow.com/questions/8449824/how-to-pre-select-an-option-in-a-dropdown-knockout-js

HTML

<select multiple data-bind="options: choices, 
                   optionsValue: 'name',
                   optionsAfterRender: $root.selectDefault">
</select>

JavaScript

var choices = [
    { id: 1, name: "one", choice: false },
    { id: 2, name: "two", choice: true },
    { id: 3, name: "three", choice: false }
    ];

function ViewModel(choices) {
   this.choices = ko.observableArray(choices);
    this.selectDefault = function(option,item){
        if(item.choice){
            ko.applyBindingsToNode(option.parentElement, {value: item.name}, item);
        }
    };
};
ko.applyBindings(new ViewModel(choices));