var USERTYPE_FORMAT = ""; //(*)

//  Input : data : UserType,
//          format : String
//  Output:
//  if data can't be formatted (for example null) return DEFAULT_RESULT;
function formatUserType(data, format) //(*)
{
	return data;
}

//  Input : data : ANY
//  Output : if data can't be parsed return null;
function parseUserType(data) //(*)
{
	return data; //:UserType
}

//function that compare op1, op2 : UserType
function compareUserType(op1, op2)
{
	return result; //-1 (op1 < op2) | 0 (op1==op2) | 1 (op1 > op2)
}; 

//Add new type Discount
var DISCOUNT_FORMAT = "%";
function formatDiscount(data, format) {
	return data + " " + format;
};

function parseDiscount(data) {
	if (Undef(data)) return 0;
	data = parseFloat(data.replace(/[^0 - 9-\ + \.]/ig, ''));
	if (isNaN(data) || data < 0) data = 0;
	if (data > 100) data = 100;
	return new Number(data);
};

function compareDiscount(op1, op2) {
	if (Undef(op1) && Undef(op2)) return 0;
	else if (Undef(op1)) return 1;
	else if (Undef(op2)) return - 1;
	if (op1 > op2) return 1;
	else if (op1 < op2) return - 1;
	else return 0;
};

//Redefine type Number, it required only integer values >=0
function parseNumber(numVal) {
	if (Undef(numVal)) return 0;
	numVal = parseInt(numVal.replace(/[^0 - 9-\ + \.]/ig, ''));
	if (isNaN(numVal) || numVal < 0) return 0
	else return new Number(numVal);
};

var gridDef =
{
	...
	colDef : [
	{
		title : "Discount",
		titleClass : "",
		type : "Discount",
		width : 0,
		alignment : "center",
		compareFunction : compareDiscount,
		isVisible : true,
		isReadOnly : false,
		useAutoIndex : false,
		useAutoFilter : false
	},
	...