Returns true if the Gregorian year is a leap year.
Uses the proleptic Gregorian rule (divisible by 4, except centuries
that are not divisible by 400) for all years, including those
before the Gregorian calendar was adopted in 1582.
Parameters
year: number
Gregorian year
Returns boolean
true if February has 29 days in year
Example
isGregLeapYear(2000); // true isGregLeapYear(2020); // true isGregLeapYear(2023); // false isGregLeapYear(2100); // false (divisible by 100 but not 400)
Returns true if the Gregorian year is a leap year.
Uses the proleptic Gregorian rule (divisible by 4, except centuries that are not divisible by 400) for all years, including those before the Gregorian calendar was adopted in 1582.