//format number
function formatNum(num) {
return Math.floor(num * 100) / 100;
}

//define variables
var initialStake = 0;
var _stake = 0;
var _comm = 5;
var _profitA = 0; // gross profit
var _netProfit = 0; // net profit
var _odds = new Array(2);
var _betType = new Array(2);
//var _toWin = new Array(2);
var _wins = new Array(2); // win amount
var _loses = new Array(2); // lose amount

//start program
function init() {
startIt(); //styles table ans sets initial values
changeIt();
}

//initialses
function startIt() {
for (i = 0; i < 2; i++){
document.arb.betType[i].style.background="#FFEECC"; // background color of back-lay action box
document.arb.wins[i].style.background="#FFEECC";
document.arb.loses[i].style.background="#FFEECC";
document.arb.stake[1].style.background="#FFEECC";
document.arb.profitA.style.background="#FFEECC";
document.arb.profitB.style.background="#FFEECC";
document.arb.netProfit.style.background="#FFEECC";
}
//sets initial settings
document.arb.odds[0].value = 4; //initial betting odds
document.arb.odds[1].value = 2; // initial lay odds
document.arb.stake[0].value = 100; // initial stake
document.arb.comm.focus(); // puts mouse at initial bet odds
}

// CHANGE FUNCTION
function changeIt() {

//get info
initialStake=formatNum(document.arb.stake[0].value);
_stake=0;
_profitA=0;
_comm=formatNum(document.arb.comm.value);

for (i = 0; i <2; i++){
_odds[i]=document.arb.odds[i].value;
_betType[i]='';
_wins[i]=0;
_loses[i]=0;
}

//checks and sets to default settings
if (_odds[0]=='' || _odds[0]==0.00 || _odds[0]>100 || _odds[0]<0) {
_odds[0]=4;
}
if (_odds[1]=='' || _odds[1]==0.00 || _odds[1]>100 || _odds[1]<0) {
_odds[1]=2;
}
if (initialStake=='' || initialStake==0.00 || initialStake>1000) {
initialStake=100;
}
if (_comm=='' || _comm==0.00 || _comm<0 || _comm>100) {
_comm=5;
}

// calcultate
_odds[0]=Number(_odds[0]);
_odds[1]=Number(_odds[1]);
_comm=Number(_comm);
_netProfit=Number(_netProfit);
_stake=initialStake*((_odds[0]+1)/(_odds[1]+1));
initialStake=Number(initialStake);

if (_odds[0]>_odds[1]) {
_wins[0]=(_odds[0]*initialStake);
_wins[1]=(_odds[1]*_stake);
_loses[0]=initialStake;
_loses[1]=_stake;
_profitA=_wins[0]-_wins[1];
_profitB=_loses[1]-_loses[0];
_profitA=formatNum(_profitA);
_profitB=formatNum(_profitA);
_netProfit=(_profitB-((_comm/100)*(_profitB)));
_netProfit=formatNum(_netProfit);
_stake=formatNum(_stake);
_betType[0]='Buy at'; // action to back
_betType[1]='Sell at'; // action to lay
}
else {
_wins[0]=(_odds[0]*initialStake);
_wins[1]=(_odds[1]*_stake);
_loses[0]=initialStake;
_loses[1]=_stake;
_profitA=_wins[1]-_wins[0];
_profitB=_loses[1]-_loses[0];
_profitA=formatNum(_profitA);
_profitB=formatNum(_profitA);
_netProfit=(_profitB-((_comm/100)*(_profitB)));
_netProfit=formatNum(_netProfit);
_stake=formatNum(_stake);
_betType[1]='Buy at'; // txt
_betType[0]='Sell at'; //txt
}

//set variable values
document.arb.netProfit.value='+'+formatNum(_netProfit); //net profit
document.arb.comm.value=_comm.toFixed(1); //exchange comm
document.arb.stake[0].value=formatNum(initialStake); // stake bet
document.arb.stake[1].value=formatNum(_stake); // stake lay
document.arb.profitA.value='+'+formatNum(_profitA); //profit
document.arb.profitB.value='+'+formatNum(_profitA);

if (_wins[0]>=_wins[1]){
document.arb.wins[0].value='+'+formatNum(_wins[0]);// if horse wins
document.arb.wins[1].value='-'+formatNum(_wins[1]);
}
else {
document.arb.wins[0].value='-'+formatNum(_wins[0]);// if horse wins
document.arb.wins[1].value='+'+formatNum(_wins[1]);
}
if (_loses[0]>=_loses[1]){
document.arb.loses[0].value='+'+formatNum(_loses[0]);// if horse loses
document.arb.loses[1].value='-'+formatNum(_loses[1]);
}
else {
document.arb.loses[0].value='-'+formatNum(_loses[0]); // if horse loses
document.arb.loses[1].value='+'+formatNum(_loses[1]); 
}
for (i = 0; i < 2; i++) {
document.arb.odds[i].value=formatNum(_odds[i]); //odds
document.arb.betType[i].value=_betType[i]; // type of bet txt
}
}