number Date.parse(string:string|mixed)
Applies ToString operator to string argument and parses the result as a date. Returns a number representing the parsed string as a number reflecting the number of milliseconds since the unix epoch from or up to the parsed date.
The function first tries to parse the date according to 15.9.1.15. If that fails it may try any implementation specific heuristic or format. Otherwise the function returns NaN.
For new Date(0,0) the following should all be equal:
x.valueOf()
Date.parse(x.toString())
Date.parse(x.toUTCString())
Date.parse(x.toISOString())
Of course, Date.parse(x.toLocaleString()) might be different.