function isNHKFloat(s){
	  var i;
    var seenDecimalPoint = false;
    var decimalPointDelimiter = ".";
    if ((s == null) || (s.length == 0))
       if (isNHKFloat.arguments.length == 1) return false;
    else return (isNHKFloat.arguments[1] == true);
    if (s == decimalPointDelimiter) return false;
    for (i = 0; i < s.length; i++)
    {   
        var c = s.charAt(i);
        if ((c == decimalPointDelimiter) && !seenDecimalPoint) seenDecimalPoint = true;
        else if (!((c >= "0") && (c <= "9"))) return false;
    }
    return true;
}

function isNHKFocus(s){
	if (!isNHKFloat(s)){
	  alert('Please enter a number!');
		return false;
	}
	return true;
}