Trying to access SceneManagement

Hi, I'm trying to access SceneManagement in Unity 5.2.3f1 but keep getting the error Assets/Scripts/0-Player/StartMenu.js(4,8): BCE0021: Namespace 'UnityEngine.SceneManagement' not found, maybe you forgot to add an assembly reference? I've tried putting the below script at the top of my .js but I still get the error, do I have to import SceneManagement ? Thanks. import UnityEngine.SceneManagement;