var whitespace = " \t\n\r";
var daysInMonth = [0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];


function isEmpty(s) {
  return ((s == null) || (s.length == 0));
}

function isWhitespace(s) {
  var i;
  if (isEmpty(s)) return true;
  for (i = 0; i < s.length; i++) {   
    var c = s.charAt(i);
    if (whitespace.indexOf(c) == -1) return false;
  }
  return true;
}

function daysInFebruary (year) {
  return (((year % 4 == 0) && ((!(year % 100 == 0)) || (year % 400 == 0))) ? 29 : 28 );
}

function isDate (year, month, day) {
  if (day > daysInMonth[month]) return false; 
  if ((month == 2) && (intDay > daysInFebruary(intYear))) return false;
  return true;
}

function openWindow(page, name, xd, yd) {
  if (navigator.appName == 'Netscape') {
    var xs = xd + 20; var ys = yd + 20;
  }
  else {
    var xs = xd + 40; var ys = yd + 30;
  }
  var xp = (640-xs)/2; var yp = (480-ys)/2;
  if (screen) {
    xp = (screen.availWidth-xs)/2;
    yp = (screen.availHeight-xs)/2;
  }
  test = window.open(page, name,'width='+xs+',height='+ys+',screenX='+xp+',screenY='+yp+',top='+yp+',left='+xp+',toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes');
}