https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/setUTCMonth
Date.prototype.setUTCMonth() - JavaScript | MDN
The setUTCMonth() method of Date instances changes the month and/or day of the month for this date according to universal time.
setutcmonth javascript mdn
https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Global_Objects/Date/setUTCMonth
Date : méthode setUTCMonth() - JavaScript | MDN
La méthode setUTCMonth() des instances de Date modifie le mois et/ou le jour du mois pour cette date selon le temps universel.
setutcmonth javascript mdn