Everything after the // is ignored when running the script.
Anything between the beginning tag /* and the end tag */ is ignored when running the script. This comment style can be used almost anywhere, even inside lists of arguments. If you place a comment inside a double-quoted string, the comment is treated merely as part of the string and not a comment. You cannot place comments in the middle of operators.
You can over-ride this comment when opening the file. Select File > Open. Hold the CTRL key while you select the JSL file and click Open. Or right-click the file in the Home Window Recent Files list and select Edit Script. The script opens into a script window instead of being executed.