function addCommas( strValue ) {

  var objRegExp  = new RegExp('(-?[0-9]+)([0-9]{3})'); 
    while(objRegExp.test(strValue)) {
       strValue = strValue.replace(objRegExp, '$1,$2');
    }
  return strValue;
}

function CalculateNow()
{
	inIncome=parseFloat(document.getElementById("myIncome").value);
	inOtherIncome=parseFloat(document.getElementById("otherIncome").value);
	inTenor=parseFloat(document.getElementById("loanPeriod").value);
	inInterest=parseFloat(document.getElementById("Interest").value);

	income = inIncome+inOtherIncome;
	incomeChk="" + income;

	if (incomeChk.indexOf('NaN')>(-1))
		income=inIncome;
		Tenor=inTenor;
		intRate=inInterest;	
		PMT=income*0.35;
		n=Tenor*12;
		i=intRate/1200;
		Result = PMT*((1-(1/Math.pow((i+1),n)))/i);
		Pv =  twoPoint("" + Result);
		Pv = addCommas(Pv)
		PMT = "" + PMT;
		PMT = addCommas(PMT)
	if (Pv.indexOf('NaN')>(-1))
		document.getElementById("result1").value="Invalid Input";
	else
		document.getElementById("result1").value=Pv ;
		document.getElementById("result2").value=PMT ;

}

function CalculateNow2(){
	ipLoanAmount=parseFloat(document.getElementById("Loan3").value);
	ipOtherIncome=parseFloat(document.getElementById("Period3").value);
	ipTenor=parseFloat(document.getElementById("Rate3").value);
	Loan=ipLoanAmount;
	Tenor=ipOtherIncome;
	intRate=ipTenor;
	PVA=Loan;
	n=Tenor*12;
	i=intRate/1200;
	Result = PVA/((1-(1/Math.pow((i+1),n)))/i)
	Pmt =  twoPoint("" + Result);
	if (Pmt.indexOf('NaN')>(-1))
		document.getElementById("result3").value="Invalid Input";
	else
		document.getElementById("result3").value=addCommas(Pmt) ;
	Result =  parseFloat(Pmt)/0.35;
	Pmt =  twoPoint("" + Result);
	
	if (Pmt.indexOf('NaN')>(-1))
		document.getElementById("result4").value="Invalid Input";
	else
		document.getElementById("result4").value=addCommas(Pmt) ;
}

function DigitCheck(myValue)
{
	i=0
	sValue = "" + myValue
	for(i=0;i<sValue.length;i++)	{
		aChar=sValue.substring(i,i+1)
		if (aChar != "." && (aChar < '0'  || aChar > '9'))	{
		        return "false"
		}
	}
}

function twoPoint(value){
	finaltotal = "" + value;
	getPoint=finaltotal.indexOf(".");
	getLength=finaltotal.length;
	if((getPoint > 0) && (getLength > getPoint+3)) 
	{
	 	if(parseInt((finaltotal.substring(getPoint+4,getPoint+5))) >= 5);
		{
			extenPoint = finaltotal.substring(getPoint+3,getPoint+4);
			finaltotal=finaltotal.substring(0,getPoint+3);
			if (parseInt(extenPoint) >= 5)
			{
				finaltotal=parseFloat(finaltotal) + 0.01;
				finaltotal="" + finaltotal;
			}
			else
				finaltotal="" + finaltotal;
			finaltotal=finaltotal.substring(0,getPoint+3);
		}
	}
	if (finaltotal.indexOf(".")<0)
		finaltotal=finaltotal+".00"
	return finaltotal;
}
<!--Hide JavaScript from Java-Impaired Browsers
var num=0;
var amt=0;
var per=0;
var months=0;
var nls="";
var rr="\r";
var b="                                    ";
//var b= "<hr>"
var d="--------------------------------------------"
+"--------------------------------------------------------";
//var s="฿";
var s="";
function removeCommas( strValue ) {

  var objRegExp = /,/g; //search for commas globally
 
  //replace all matches with empty strings
  return strValue.replace(objRegExp,'');
}

function removeCurrency( strValue ) {

  var objRegExp = /\(/;
  var strMinus = '';
 
  //check if negative
  if(objRegExp.test(strValue)){
    strMinus = '-';
  }
  
  objRegExp = /\)|\(|[,]/g;
  strValue = strValue.replace(objRegExp,'');
  if(strValue.indexOf(s) >= 0){
    strValue = strValue.substring(1, strValue.length);
  }
  return strMinus + strValue;
}

function addCurrency( strValue ) {

  var objRegExp = /-?[0-9]+\.[0-9]{2}$/;
   
    if( objRegExp.test(strValue)) {
      objRegExp.compile('^-');
      strValue = addCommas(strValue);
      if (objRegExp.test(strValue)){
        strValue = '(' + strValue.replace(objRegExp,'') + ')';
      }
      return s + strValue;
    }
    else
      return strValue;
}


function iA(){
 this.length=iA.arguments.length;
 for (var i=0;i<this.length;i++){
  this[i]=iA.arguments[i];
  }
 }
var pwr=new iA(10);
var dec=new iA(16);
pwr[0]=1;
for (var i=0;i<9;i++){
 pwr[i+1]=pwr[i]*10;
}
dec[0]=.1;
dec[1]=.01;
dec[2]=.001;
dec[3]=.0001;
dec[4]=.00001;
dec[5]=.000001;
dec[6]=.0000001;
dec[7]=.00000001;
dec[8]=.000000001;
dec[9]=.0000000001;
dec[10]=.00000000001;
dec[11]=.000000000001;
dec[12]=.0000000000001;
dec[13]=.00000000000001;
dec[14]=.000000000000001;
dec[15]=.0000000000000001;
   
var ns="01234567890";
var cr="";
var str="";

function stn(){
 num=0;
 pos=str.indexOf(".");
 sfx="";
 if (pos>-1){
  sfx=str.substring(pos+1,str.length);
  str=str.substring(0,pos);
  }
 strl=str.length;
 for (var i=strl-1;i>-1;i--){
  cr=str.substring(i,i+1);
  pos=ns.indexOf(cr);
  num+=pos*pwr[strl-i-1];
  }
  if (sfx!=""&&sfx.length>dp){
   pos=ns.indexOf(sfx.charAt(dp+1));
   if (pos>4){
    pos=ns.indexOf(sfx.charAt(dp));
    sfx=sfx.substring(0,dp-1)+(pos+1);
    }
   }
  if (sfx!=""){
   for (var i=0;i<dp;i++){
    cr=sfx.substring(i,i+1);
    pos=ns.indexOf(cr);
    num+=pos*dec[i];
    }
  }
 }
 
function ClearForm(form){
document.isn.amt.value.value="";
document.isn.per.value="";
document.isn.months.value="";
MyText.innerText = ""  ;
//document.isn.myText.value = "";
}

function testIt(form){
//	alert(form);
 str=document.getElementById("amtBox4").value;
 str = "" + str;
 str = removeCommas(str);
 fmtIt();
 bl=str.length+3;
 dp=2;
 stn();
 amt=num;
 str=document.getElementById("InterestBox4").value;
 dp=4;
 stn();
 per=num;
 str=document.getElementById("periodBox4").value;
 dp=0;
 stn();
 months=num;
 if (months<1||months>999||per<.0001||per>99||amt<1||amt>pwr[9]){
  alrt();
  }
 else{
 computeForm();
 }
}

function computeForm(){
 ls="";
 isnnum=1;
 i=per/12/100;
 fpv=0;
 
 for (var j=0;j<months;j++)
  isnnum=isnnum*(1+i);
  tmp=(amt*isnnum*i)/(isnnum-1);
  fpv+=tmp;
  fcalc=((months*fpv)-amt);
  
 prtSched();
 }
 
function prtSched(){
 fpv+=.01;
 str=""
 str+=fpv;
 fmtIt();
 dp=2;
 stn();
 fpv=num;
 pct=per/12/100;
 if (bl<14){
  bl=14;
  }
 hdr =" ตารางอัตราผ่อนชำระ : "+document.getElementById("periodBox4").value 
 +" เดือน"+ "ในการชำระหนี้ "+document.getElementById("amtBox4").value 
 +" บาท"+ rr+"ที่อัตราดอกเบี้ยที่ "+document.getElementById("InterestBox4").value+"%."+rr+d+rr
 +"งวดที่       ผ่อนชำระ        ดอกเบี้ย      เงินต้นที่ลดลง     ยอดคงเหลือ "
 +rr+d+rr;
 for (var j=0;j<months;j++){
  ntr=(amt*pct);
  str="";
  str+=ntr;
  fmtIt();

  ntr1=addCurrency(str);
  prp=fpv-ntr;
  if (prp>amt){
   prp=amt;
   }
  str="";
  str+=prp;
  fmtIt();
  prp1=addCurrency(str);
  amt-=prp;
  str="";
  str+=amt;
  fmtIt();
  amt1=addCurrency(str);
  if (fpv>(ntr+prp)){
   fpv=ntr+prp;
   }
  str="";
  str+=fpv;
  fmtIt();
  fpv1=addCurrency(str);
  str="";
  str+=(j+1)+".";
  ls+=b.substring(0,2)+str+b.substring(0,12-str.length)
  +fpv1+b.substring(0,14-fpv1.length)+ntr1
  +b.substring(0,14-ntr1.length)+prp1
  +b.substring(0,14-prp1.length)+amt1
  +rr;
  } 
  MyHeader.innerText = hdr;
  MyText.innerText = ls+d+rr  ;
   //document.isn.MyText.value = ls+d+rr  ;
 }
function fmtIt(){
 pos=str.indexOf(".");
 if (pos==0){
  str="0"+str;
  pos++;
  }
 if (pos<0){
  str+=".00";
  pos=str.indexOf(".");
  }
 str+="0000";
 str=str.substring(0,pos+4);
 cr=str.charAt(str.length-1);
 pos=ns.indexOf(cr);
 str=str.substring(0,str.length-1);
 if (pos>5){
  fmtIt1();
  }
 }
 function fmtIt1(){
  for (var k=str.length-1;k>-1;k--){
   cr=str.charAt(k);
   posn=ns.indexOf(cr);
   if (posn<0){
    k--;
   }
   else{
    str=str.substring(0,k)+ns.substring(posn+1,posn+2)
    +str.substring(k+1,str.length);
    if (posn!=9){
     k=-1;
    }
   }
  }
 }
function alrt(){
 alert("ระยะกู้ยืมอยู่ระหว่าง 1 ถึง 999 เดือน  และ อัตราดอกเบี้ยอยู่ระหว่าง .001 ถึง 99 %");
}
//-->