日期是困难的，我总是建议使用专门用于日期处理的库，因为它降低了代码中出错的可能性。

MomentJS是一个很好的选择。

var now = moment();
var input = moment("2016-04-17T11:45:00Z");
var isThisWeek = (now.isoWeek() == input.isoWeek())

编辑：请注意，截至2020年，Moment可能不是新项目的良好选择

这似乎对我很管用。

function isDateInThisWeek(date) {
  const todayObj = new Date();
  const todayDate = todayObj.getDate();
  const todayDay = todayObj.getDay();

  // get first date of week
  const firstDayOfWeek = new Date(todayObj.setDate(todayDate - todayDay));

  // get last date of week
  const lastDayOfWeek = new Date(firstDayOfWeek);
  lastDayOfWeek.setDate(lastDayOfWeek.getDate() + 6);

  // if date is equal or within the first and last dates of the week
  return date >= firstDayOfWeek && date <= lastDayOfWeek;
}

const date = new Date();
const isInWeek = isDateInThisWeek(date);