Getting a reference error while calling a function in jQuery

I am trying to call 'A' function from 'B' function in JQuery. The function 'A' is defined before the 'B' function. But whenever I try to run the 'B' functions script, I am getting a reference error : 'A' function not defined.

Here is the code of both 'A' as well as 'B' function.

Here

'A'= calcGST(); & 'B'=SetDefault();

I have also attached the console's error below.

function SetDefault(a, Text)
{

   var z = Number(1); 
   console.log("count"+$("#icount").val());
   console.log("count "+$("#icount").val());
   var subtot=0;var TaxAmt=0;
   for(z=1; z<=$("#icount").val();z++)
   {

       var inv = $("#invqty"+z).val();           
       if(inv==null)
       {
      inv=0;
   }             

       var rt= $("#rate"+z).val();

       if(rt==null)
       {
          rt=0;
       }

           var at = inv*rt;

           $("#amt"+z).val(at);
           subtot=at+subtot;

   }
   console.log(subtot);
   document.getElementById("subtot").value=subtot;
   calcGST();


}

Here is my calcGST()-

function calcGST()
{
    var hsncode = $("input[name='hsncode[]']").map(function(){return $(this).val();}).get();
              console.log("HSNCode "+ hsncode);
    var hsnper = $("input[name='hsnper[]']").map(function(){return $(this).val();}).get();
              console.log("HSNPer "+ hsnper);
    var hsnamt = $("input[name='amt[]']").map(function(){return $(this).val();}).get();
          console.log("HSNAmt "+ hsnamt);


functionToSetAllGstValue(hsnamt, hsncode, hsnper);
//alert("Called");

 document.getElementById("gtotal1").value=0.0;
   var cgst_per = document.getElementById("cgst").value;//Central Tax Percent
  console.log("cgst_per"+cgst_per);
  var sgst_per = document.getElementById("sgst").value;//State Tax Percent

  var subtot = document.getElementById("subtot").value;//Sub Total
  console.log("subtot"+subtot);
   var sgst_amt=((sgst_per/100)*subtot); 
   console.log("sgst_amt"+ sgst_amt);
  document.getElementById("sgstamt").value=sgst_amt.toFixed(2);
   var cgst_amt=((cgst_per/100)*subtot);
  document.getElementById("cgstamt").value=cgst_amt.toFixed(2);
  var gtotal = Number(subtot)+Number(cgst_amt)+Number(sgst_amt);
   //var ramt=gtotal-($subtotal+taxamt+cgst+sgst);
   gtotal = Math.round(gtotal);
  //alert("gtotal "+gtotal);
   document.getElementById("gtotal1").value = gtotal.toFixed(2);

    var ramt=gtotal-(Number(subtot)+Number(cgst_amt)+Number(sgst_amt));
    document.getElementById("ramt").value = ramt.toFixed(2);

    //alert(ramt.toFixed(2));

}

Here is my console error :

ReferenceError: calcGST is not defined[Learn More]  new_tax_invoice.php:853:4
SetDefault http://vijayneetigroup.com/ERP/rugwed/pages/new_tax_invoice.php:853:4
onchange http://vijayneetigroup.com/ERP/rugwed/pages/new_tax_invoice.php:1:1

Please guide me.

Thanks in advance.