function isNull(val){
	if(val == null)
		return true;
	return false;
}
function isEmpty(val){
	if(!isNull(val) && trim(val) != "")
		return false;
	return true;
}
function trim(stringToTrim) {
	if(isNull(stringToTrim))
		return "";
	return stringToTrim.replace(/^\s+|\s+$/g,"");
}
function ltrim(stringToTrim) {
	if(isNull(stringToTrim))
		return "";
	return stringToTrim.replace(/^\s+/,"");
}
function rtrim(stringToTrim) {
	if(isNull(stringToTrim))
		return "";
	return stringToTrim.replace(/\s+$/,"");
}
function isNumeric(val){
	if(!isEmpty(val) && !isNaN(val))
		return true;
	return false;
}
function isValidIP(str) {
	var re = new RegExp(/^\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b$/);
	if (str.match(re)) {
		return true;
	}
	return false;
}
function isValidEmail(str)
{
	apos=str.indexOf("@");
	dotpos=str.lastIndexOf(".");
	if (apos<1||dotpos-apos<2) {
		return false;
	}	else {
		return true;
	}	
}
function strToBoolean(str){
	str = trim(str);
	if(!isEmpty(str))
		if(str.toLowerCase() == "true")
			return true;
	return false;
}
function isArray(obj) {
	if (obj.constructor.toString().indexOf("Array") == -1)
		return false;
	else
		return true;
}

//isIntegerInRange (STRING s, INTEGER a, INTEGER b)
function isIntegerInRange (s, a, b)
{
	if (isEmpty(s))
		if (isIntegerInRange.arguments.length == 1)
			return false;
		else
			return (isIntegerInRange.arguments[1] == true);

	// Catch non-integer strings to avoid creating a NaN below,
	// which isn't available on JavaScript 1.0 for Windows.
	if (!isInteger(s, false))
		return false;

	// Now, explicitly change the type to integer via parseInt
	// so that the comparison code below will work both on
	// JavaScript 1.2 (which typechecks in equality comparisons)
	// and JavaScript 1.1 and before (which doesn't).
	var num = parseInt (s);
	return ((num >= a) && (num <= b));
}

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

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 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];
	
	// The next line is a bit byzantine.  What it means is:
	// a) s must be a signed integer, AND
	// b) one of the following must be true:
	//    i)  s is empty and we are supposed to return true for
	//        empty strings
	//    ii) this is a positive, not negative, number
	
	return (isSignedInteger(s, secondArg) && ( (isEmpty(s) && secondArg)  || (parseInt (s) > 0) ) );
}

function isNonnegativeInteger (s)
{
	var secondArg = false;
	
	if (isNonnegativeInteger.arguments.length > 1)
		secondArg = isNonnegativeInteger.arguments[1];
	
	// The next line is a bit byzantine.  What it means is:
	// a) s must be a signed integer, AND
	// b) one of the following must be true:
	//    i)  s is empty and we are supposed to return true for
	//        empty strings
	//    ii) this is a number >= 0
	
	return (isSignedInteger(s, secondArg) && ( (isEmpty(s) && secondArg)  || (parseInt (s) >= 0) ) );
}