Creating a Script
Select Scripts from the library drop down menu. Then click the + button next to Scripts. This will prompt for a Name to give the new script, a Description for the new script (this is optional), and a Type (Behavior or Vine) for the new script. Once these fields have been populated, click the Create! button at the bottom right of the library panel. This will create a new script in the script library with the selected name, description, and type.
Attaching a Script
Create or select an asset element you wish to attach a script to. At the bottom of its inspector you will see a box that says Drop script here. From the script library, click and drag your script to the script section of the inspector and place it on the target box.
To edit a script, either select the edit icon (pencil icon) on the script thumbnail or select the script and click the edit icon in the inspector panel. This will open the script editor which can be directly type into while still viewing the canvas.
Once you have written or made changes to a script, you will have to save it to see its effects in the canvas. To save a script, click File > Save. Saving a script will cause the canvas to reload the script.
There is an Autosave toggle in the File menu that can be turned on which will periodically save the script and update the canvas. However Autosave is not recommended for use with Behavior scripts as saving an incomplete Behavior script is likely to cause more errors and unexpected behavior than saving an incomplete Vine script.
You can use [CTRL] + [Space] to trigger autocomplete.
Please note this autocomplete is not like IntelliSense. It does not attempt to fully analyze your code to give only intelligent suggestions or give you detailed parameter information. It will try to identify local keywords in your code as well as offer completion for common keywords and functions.
For a complete JS API reference, see the API documentation.