prototype Date conversions & single digit padleft

[jmrker]

I have noticed a number of forum members wanting to change the date format.
Here is a small prototype function to form date into YYYYMMDD and DDMMYYYY formats.
Function includes an optional separator character for the display.
Others can be created with a bit of re-arrangement.

Also added a function to add or subtract a number of days from the chosen date.

Also includes a number padding function so that numbers less than 10 are padded with one '0' to the left of the number.
This could be an optional or stand alone function.

<script type="text/javascript">
Number.prototype.padDigit = function() {
  var n = this;  
  return n = (n < 10) ? '0'+n : n; 
}
Date.prototype.toYYYYMMDD = function(sep) {
  var y = this.getFullYear();
  var m = this.getMonth()+1;
  var d = this.getDate();
  return ''+y+sep+m.padDigit()+sep+d.padDigit();
}
Date.prototype.toDDMMYYYY = function(sep) {
  var y = this.getFullYear();
  var m = this.getMonth()+1;
  var d = this.getDate();
  return ''+d.padDigit()+sep+m.padDigit()+sep+y;
}
Date.prototype.addDays = function (days) {
  return new Date(this.getTime() + days*24*60*60*1000);
}

// testing code
var str = '';
    str = new Date().toYYYYMMDD('');  // Current date and Aug. 1, 2011
    str += '\n'+new Date(2011,7,1).toYYYYMMDD('/');
    str += '\n\n';
    str += new Date().toDDMMYYYY('-');  // Current date and Aug. 3, 2012
    str += '\n'+new Date(2012,7,3).toDDMMYYYY('');
    str += '\n\n';
    str += new Date().toDDMMYYYY('_');  // Current date and Aug. 16, 2012
    str += '\n'+new Date(2012,7,16).toYYYYMMDD('.');
    str += '\n\n';
    str += new Date('Aug 16, 2011').toYYYYMMDD('.');  // Aug. 16, 2011 and Aug. 3, 2012
    str += '\n'+new Date('Aug 3, 2012').toYYYYMMDD('/');
    str += '\n\n';
var today = new Date();
    str += today.toYYYYMMDD('');              // Current date
    str += '\n';
    str += today.addDays(14).toYYYYMMDD('');  // plus 2 weeks
    str += '\n';
    str += today.addDays(-14).toYYYYMMDD('');  // minus 2 weeks
alert(str);
</script>