How to Sort an Array of Dates with JavaScript

onpubcom_array_date_sort.js

<script type="text/javascript">

// First let's create an array of JavaScript Date
// objects.
// More info about the Date class:
// http://w3schools.com/js/js_obj_date.asp
var dates = [
new Date(2010, 4, 10, 10, 07, 16),
new Date(2010, 4, 8, 9, 16, 09),
new Date(2010, 3, 30, 0, 15, 49),
new Date(2010, 3, 8, 10, 08, 35)];

// Now we will define our date comparison functions. These are callbacks
// that we will be providing to the array sort method below.
var date_sort_asc = function (date1, date2) {
  // This is a comparison function that will result in dates being sorted in
  // ASCENDING order. As you can see, JavaScript's native comparison operators
  // can be used to compare dates. This was news to me.
  if (date1 > date2) return 1;
  if (date1 < date2) return -1;
  return 0;
};

var date_sort_desc = function (date1, date2) {
  // This is a comparison function that will result in dates being sorted in
  // DESCENDING order.
  if (date1 > date2) return -1;
  if (date1 < date2) return 1;
  return 0;
};

// Finally, we are now able to call the sort method on our array of dates.
// More info about array sorting: http://w3schools.com/jsref/jsref_sort.asp

// First let's sort the array in ascending order.
dates.sort(date_sort_asc);

// Now let's output the results to the page to show that the dates are now
// sorted in ascending order.
document.write('<p>Dates sorted in ascending order (oldest to newest):</p>');
for (var i = 0; i < dates.length; i++) {
  document.write(i + ': ' + dates[i] + '<br>');
}

// Now let's sort the dates in descending order and output the results.
dates.sort(date_sort_desc);

document.write('<p>Dates sorted in descending order (newest to oldest):</p>');
for (var i = 0; i < dates.length; i++) {
  document.write(i + ': ' + dates[i] + '<br>');
}

// That's all there is to it!
// From: http://onpub.com/index.php?s=7&a=109

</script>