This method returns a string value containing a GMT representation of the date and time value in the receiving object. The contents of the string are implementation-dependent, but are intended to represent the date in a convenient, human-readable form. However, this method is now deprecated in favor of Date.toUTCString() which should be used in preference. It is provided merely for compatibility with older systems.
As of ECMA edition 3 it is no longer included in the standard although implementations may still provide it for backwards compatability.