将Javascript对象转换为Javascript数组

I am using a knockout observable array to populate a dropdownlist.The dropdownlist gets populated if I hardcode the array values.But I am now trying to get the data from the database.I am using JSON format for the javascript object.I am accessing a single property of the javascript object i.e; Certification and I am creating an array which I am passing back to a script.But each time the value that is passed back is undefined whereas the array shows up in the console.I am using a knockout observable array to popul