//
// check for white space utility
function iswhite(s)
{ for (var i = 0; i < s.length; i++)
  { var c = s.charAt(i);
	if ((c != ' ') && (c != '\n') && (c != '\t')) return false;
  }
  return true;
}
//
// check for blanks utility
function isblanks(p)
{ if ( (p == null) || (p == "") || iswhite(p) )
  { return true;
  }
}
//
// check for letters and numbers utility
function isletters(s)
{ var charallowed = "abcdefghijklmnopqrstuvwxyz0123456789";
  for (var i = 0; i < s.length; i++)
  { var c = s.charAt(i);
	if (charallowed.indexOf(c) == -1) return false;
  }
  return true;
}
//
// check email format utility
function errEmail(e)
{ var x = e.indexOf("@");
  if ( x == -1 ) return true;
  e = e.substr(x);
  if ( e.indexOf(".") == -1 ) return true;
  x = e.lastIndexOf(".") + 1;
  e = e.substr(x);
  if ( (e.length < 2) || (e.length > 4) ) return true;
  return false;
}