ECMAScript defines a string interchange format for date-times based upon a simplification of the ISO 8601 Extended Format. The format is as follows: YYYY-MM-DDTHH:mm:ss.sssZ
— https://www.ecma-international.org/ecma-262/5.1/#sec-15.9.1.15
So what exactly is the difference between the two formats? What do I have to be careful about? I noticed that ISO 8601 states that the T can be substituted by a space. What else is "simplified"?
To be very specific: This question is about the standard. Browser behavior is interesting, but not the main focus of this question.