Returns a date converted to a string using Greenwich Mean Time (GMT).
function toGMTString() : String
The toGMTString method is obsolete, and is provided for backwards compatibility only. It is recommended that you use the toUTCString method instead.
The toGMTString method returns a String object that contains the date formatted using GMT convention. The format of the return value is as follows: "05 Jan 1996 00:00:00 GMT."