populate dropdowns using Knockout.js

I am new to Knockout.js can anyone let me know how can we populate b dropdowns using Knockout.js. I have two dropdowns : Employee and Course.

<select id="Employee">
                    <option value="1" selected="selected">1</option>
                    <option value="2">2</option>

                </select>

<select id="Course">
                    <option value="Course1" selected="selected">Course1</option>
                    <option value="Course12">Course12</option>

                </select>

so my requirement is if i select Employee "1开发者_StackOverflow" then i should be able to see only Course1. if i select Employee "2" i should be able to see both Course1 and Course2.

Without more information about your view model, it is pretty hard to answer, but this could be your javascript:

(function (myViewModel, $, undefined) {
    myViewModel.selectedEmployee = ko.observable(1);
    myViewModel.courses = ko.dependentObservable(function () {
        var result = ["Course1"];
        if (myViewModel.selectedEmployee() === '2') {
            result.push("Course2");
        }
        return result;
    });        
}(window.myViewModel = window.myViewModel || {}, jQuery));
ko.applyBindings(myViewModel);

and then your HTML:

<select id="Employee" data-bind="value: selectedEmployee">
    <option value="1" selected="selected">1</option>
    <option value="2">2</option>
</select>

<select id="Course" data-bind="options: courses"></select>