var

	principal,

	targetRate,

	realRate,

	period,

	interestRate,

	reward=0;

	

function formatMoney(inVal){

	strIn = new String(inVal);

	if ( strIn.indexOf(".") == -1 ){

		dollar = strIn;

		cent = "";

	}else{

		dollar = strIn.substring(0,strIn.indexOf("."));

		cent = strIn.substring(strIn.indexOf("."),strIn.length);

	}

	count = dollar.length%3;

	if ( count == 0 ){

		count = 3;

	}

	result = dollar.substring(0,count);

	count += 3;

	while ( count <= dollar.length ){

		result += ",";

		result += dollar.substring(count-3,count);

		count += 3;

	}

	result += cent;

	return result;

}



function changePrincipal(){

	principal = parseInt(document.forms[1].principal.value);

	if ( isNaN(eval(principal)) ){

		document.forms[1].principal.focus();

		document.forms[1].principal.select();

		alert("Invalid input");

		return false;

	}else{

		document.forms[1].principal.value = principal;

		return true;

	}

}

function changeTargetRate(){

	targetRate = parseFloat(document.forms[1].targetRate.value);

	if ( isNaN(eval(targetRate)) ){

		document.forms[1].targetRate.focus();

		document.forms[1].targetRate.select();

		alert("Invalid input");

		return false;

	}else{

		document.forms[1].targetRate.value = targetRate;

		return true;

	}

}

function changeRealRate(){

	realRate = parseFloat(document.forms[1].realRate.value);

	if ( isNaN(eval(realRate)) ){

		document.forms[1].realRate.focus();

		document.forms[1].realRate.select();

		alert("Invalid input");

		return false;

	}else{

		document.forms[1].realRate.value = realRate;

		return true;

	}

}

//function changePeriod(){

//	period = parseInt(document.forms[1].period.value);

//	if ( isNaN(eval(period)) ){

//		document.forms[1].period.focus();

//		document.forms[1].period.select();

//		alert("Invalid input");

//		return false;

//	}else{

//		document.forms[1].period.value = period;

//		return true;

//	}

//}

function changeInterestRate(){

	interestRate = parseFloat(document.forms[1].interestRate.value);

	if ( isNaN(eval(interestRate)) ){

		document.forms[1].interestRate.focus();

		document.forms[1].interestRate.select();

		alert("Invalid input");

		return false;

	}else{

		document.forms[1].interestRate.value = interestRate;

		return true;

	}

}

function changeReward(){

	document.forms[1].reward.value = reward;

}

function calc(){

	if ( !changePrincipal() ){

		return;

	}

	if ( !changeTargetRate() ){

		return;

	}

	if ( !changeRealRate() ){

		return;

	}

//	if ( !changePeriod() ){

//		return;

//	}

	period = document.forms[1].period.options[document.forms[1].period.selectedIndex].value;

	if ( !changeInterestRate() ){

		return;

	}

	if ( realRate >= targetRate ){

		document.forms[1].reward.value = formatMoney(Math.round(principal * (1.0 + interestRate / 100 * period / 365.0) * 100) / 100);

		document.forms[1].reward.value = document.forms[1].reward.value + "HKD";

	}else{

		document.forms[1].reward.value = formatMoney(Math.round(principal * (1.0 + interestRate / 100 * period / 365.0) / targetRate * 100) / 100);

		document.forms[1].reward.value = document.forms[1].reward.value + " " + document.forms[1].hooked.options[document.forms[1].hooked.selectedIndex].text;

	}

}