SharePoint Development & Administration + InfoPath

//Convert the date value passed as a parameter
//into ISO 8601 standard.
//
//Pass NULL as the date parameter to return the
//current date and time in ISO 8601 format
//----------------------------------------
function getDateTime(date)
{
  if (date != null)
  {
     //Date value supplied
     d = date;
  }
  else
  {
     //No date supplied, Create new date object
     d = new Date();
  }

  //Generate ISO 8601 date/time formatted string
  var s = "";

  s += d.getYear() + "-";          
  s += d.getMonth() + 1 + "-";
  s += d.getDate();
  s += "T" + d.getHours() + ":";
  s += d.getMinutes() + ":";

  //Replace the "Z" below with the required
  //time zone offset (eg "+10:00" - Australian EST)
  s += d.getSeconds() + "Z";

  //Return the ISO8601 date string
  return s;
}