$("#DropDown").bind('change', function () {
    var id = $("#DropDown option:selected").val();
    var text = $("#DropDown  option:selected").text();

    $.ajax({
        url: '/ControllerName/MethodName?id=' + id + "&text=" + text,
        contentType: 'application/html; charset=utf-8',
        type: 'GET',
        dataType: 'html'
    }).success(function (result) {
        //Do something with the result
    })
});