var d = '2017-02-31';
console.log(d, Date.parse(d));

var d = '2017-02-32';
console.log(d, Date.parse(d));

var d = '2017-02-31';
return d == new Date(d).toISOString().slice(0,10);

function isRusDate(s) {
  try {
    s = s.trim();
    if (s.length != 10) {return false;}
    var d_arr = s.slice(-10).split('.');
    s = d_arr[2] +'-'+ d_arr[1] +'-'+ d_arr[0];
    return s == new Date(s).toISOString().slice(0,10);
  } catch(e) {return false;}
}