phpjs/functions/datetime/checkdate.js

php.js offers community built php functions in javascript

function checkdate(m, d, y) {
  // From: http://phpjs.org/functions
  // +   original by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // +   improved by: Pyerre
  // +   improved by: Theriault
  // *     example 1: checkdate(12, 31, 2000);
  // *     returns 1: true
  // *     example 2: checkdate(2, 29, 2001);
  // *     returns 2: false
  // *     example 3: checkdate(3, 31, 2008);
  // *     returns 3: true
  // *     example 4: checkdate(1, 390, 2000);
  // *     returns 4: false
  return m > 0 && m < 13 && y > 0 && y < 32768 && d > 0 && d <= (new Date(y, m, 0)).getDate();
}