https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date

A string value representing a date, specified in a format recognized by the Date.parse() method (these formats are IETF-compliant RFC 2822 timestamps and also strings in a version of ISO8601).
Note: Parsing of date strings with the Date constructor (and Date.parse(), which works the same way) is strongly discouraged due to browser differences and inconsistencies. Support for RFC 2822 format strings is by convention only. Support for ISO 8601 formats differs in that date-only strings (e.g. "1970-01-01") are treated as UTC, not local.

两种格式是不一样的，最好直接用 moment 或 date.js 等类库并显式指定格式。