function isWhitespace (s)
{   var i;
    var whitespace = " \t\n\r";
    
    // Is s empty?  
    if (isEmpty(s)) return true; 
    
    // Search through string's characters one by one    
    // until we find a non-whitespace character.  
    // When we do, return false; if we don't, return true. 
    for (i = 0; i < s.length; i++)
    {
        // Check that current character isn't whitespace.  
        var c = s.charAt(i); 
        if (whitespace.indexOf(c) == -1) return false; 
    }    
    // All characters are whitespace.  
    return true; 
} 
function isEmpty(s)
{
	return ((s == null) || (s.length == 0));
}
function isDigit (c)
{
	return ((c >= "0") && (c <= "9"));
}
function isInteger (s)
{
	var i;
    if (isEmpty(s))
       if (isInteger.arguments.length == 1) return false;
       else return (isInteger.arguments[1] == true);

    for (i = 0; i < s.length; i++)
    {
        var c = s.charAt(i);
        if (!isDigit(c)) return false;
    }
    // All characters are numbers.
    return true;
}