//	isDigit
//	isInteger
//	isSignedInteger
//	isPositiveInteger
//	isNonnegativeInteger
//	isNegativeInteger
//	isNonpositiveInteger
//	isIntegerInRange
//	checkemail
//-----------------------------------------------

function checkemail(str){
	var filter=/^.+@.+\..{2,3}$/
	return (filter.test(str))
  }

function isSignedInteger (s){
	if (isEmpty(s))
		if (isSignedInteger.arguments.length == 1) return false;
		else return (isSignedInteger.arguments[1] == true);
	else {
		var startPos = 0;
		var secondArg = false;
		if (isSignedInteger.arguments.length > 1)  secondArg = isSignedInteger.arguments[1];
		// skip leading + or -
		if ( (s.charAt(0) == "-") || (s.charAt(0) == "+") ) startPos = 1;
		return (isInteger(s.substring(startPos, s.length), secondArg))
      	}
}

function isPositiveInteger (s){
	var secondArg = false;
	if (isPositiveInteger.arguments.length > 1) secondArg = isPositiveInteger.arguments[1];
	return (isSignedInteger(s, secondArg) && ( (isEmpty(s) && secondArg)  || (parseInt (s) > 0) ) );
   }


function isInteger (s){
	var i;
	if (isEmpty(s))
	if (isInteger.arguments.length == 1) return 0;
	else return (isInteger.arguments[1] == true);
	for (i = 0; i < s.length; i++)
	{
		var c = s.charAt(i);
		if (!isDigit(c)) return false;
	}
	return true;
}

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

function isDigit (c){
	return ((c >= "0") && (c <= "9"))
}

function trim(s) {
  while (s.substring(0,1) == ' ') {
    s = s.substring(1,s.length);
  }
  while (s.substring(s.length-1,s.length) == ' ') {
    s = s.substring(0,s.length-1);
  }
  return s;
}