date format

example.js

var val = someUserInput

// Check to see if a valid timestamp was used
if (!isNaN(+val)) {
  if (val.length === 13 || val.length === 10) {
    return new Date(val.length === 10 ? +val * 1000 : +val);
  }
}

// Check if the string could be parsed by the date formatter
var parsed = dateFormat(val);
if (parsed) {
  return new Date(parsed);
}

// Check if the string could be parsed as a Date object
var parsed = Date.parse(val);
if (!isNaN(parsed)) {
  return new Date(parsed);
}

index.js

function dateFromString(str) {
  var rx = /[0-9]{2,4}[\/-][0-9]{2}[\/-][0-9]{2,4}(\s?[0-9]{2}:[0-9]{2}(:[0-9]{2})?(\s?[a-zA-Z]{3})?)?/
    , defaults = [null, ' 00:00', ':00', ' UTC']
    , match = str.match(rx)
    ;
  if (!match) {
    return false;
  }
  for (var i = 1; i < match.length; i++) {
    if (!match[i]) {
      match[i] = defaults[i]
      match[0] += defaults[i]
    }
  }
  return match[0]
}

test.js

var assert = require('assert')

;['02-20-2012'
, '2012-02-20 00:00'
, '02-20-2012 00:00'
, '02-20-2012 00:00:00'
, '02-20-2012 00:00:00 UTC'
].forEach(function(x) {
  var str = dateFromString(x)
  assert.strictEquals(1329696000000, +new Date(str), 'Mismatch for: ' + x)
})