Converting 24 hour time to 12 hour time w/ AM & PM using Javascript

Question

What is the best way to convert the following JSON returned value from a 24-hour format to 12-hour format w/ AM & PM? The date should stay the same - the time is the only thing that needs formatting.

February 04, 2011 19:00:00

P.S. Using jQuery if that makes it any easier! Would also prefer a simple function/code and not use Date.js.

Answer 1

UPDATE 2: without seconds option

UPDATE: AM after noon corrected, tested: http://jsfiddle.net/aorcsik/xbtjE/

I created this function to do this:

function formatDate(date) {
  var d = new Date(date);
  var hh = d.getHours();
  var m = d.getMinutes();
  var s = d.getSeconds();
  var dd = "AM";
  var h = hh;
  if (h >= 12) {
    h = hh - 12;
    dd = "PM";
  }
  if (h == 0) {
    h = 12;
  }
  m = m < 10 ? "0" + m : m;

  s = s < 10 ? "0" + s : s;

  /* if you want 2 digit hours:
  h = h<10?"0"+h:h; */

  var pattern = new RegExp("0?" + hh + ":" + m + ":" + s);

  var replacement = h + ":" + m;
  /* if you want to add seconds
  replacement += ":"+s;  */
  replacement += " " + dd;

  return date.replace(pattern, replacement);
}

alert(formatDate("February 04, 2011 12:00:00"));