$(".custom-dob-field input").on("change",function (event) {
	// validate date: dd/mm/yyyy
	var $parent = $(this).parent();
	var a = $(this).val().split('/');

	if( a.length != 3 ) {
		//console.log('invalid format: a.length != 3');
		$parent.addClass('custom_validation_error_date');
		return;
	} else {

		var d = a[0],
			m = a[1],
			y = a[2];

		if( d.length != 2 || m.length != 2 || y.length != 4 ) {
			//console.log('invalid format: d.length != 2 || m.length != 2 || y.length != 4');
			$parent.addClass('custom_validation_error_date');
			return;
		}

		var dn = parseInt(d),
			mn = parseInt(m);

		if( dn > 31 || dn > 12 ) {
			//console.log('invalid format: dn > 31 || dn > 12');
			$parent.addClass('custom_validation_error_date');
			return;
		}
	}

	$parent.removeClass('custom_validation_error_date');
});