function isRutDigit (c)
{
	return ((c >= "0") && (c <= "9") || (c=="k") || (c=="K") )
}


function isRut (s)
{
    if (isEmpty(s)) 
       if (isRut.arguments.length == 1) return defaultEmptyOK;
       else return (isRut.arguments[1] == true);
    if (isWhitespace(s)) return false;
    var i = 1;
    var sLength = s.length;

    while ((i < sLength) && (s.charAt(i) != "-") && (isDigit(s.charAt(i))) )
    { i++
    }
    
    
    if ( (s.charAt(i) == "-") && ( (i+1)==(sLength-1) ) && (isRutDigit(s.charAt(i+1)) ) )return true;
    else return false;
}