JS function error in separate .js file

[NewHeart42108]

I have a javascript function that works fine when it is included in a <script></script> statement in the header of my php file, but when I move it to a separate .js file, it throws two errors.

The function is

function calculate()
{
  var i
  var optCount = <?php echo $opt_count ?>;
  var listItems = '<?php echo json_encode($lineItems); ?>';
   var listArray = JSON.parse(listItems);
    var itemQty = '';
    var itemPrice = '';
  var itemTot = '';
  var orderTot = '';
  var orderTotNum = 0;

  for(i=0; i<=optCount; i++){
     var qtyIndex = 'qty' + i;
    var qtyID = document.getElementById(qtyIndex).value;
   if (qtyID > 0){
      theQuantity = qtyID;
      qtyID =eval(theQuantity);
    } else {
      theQuantity = 0;
      qtyID = '';
    }
     var thePrice = listArray[i]["price"];

    var itemTot = theQuantity * thePrice;
     var totalIndex = 'total' + i;
     var elem = document.getElementById(totalIndex);
     if(itemTot > 0){
             elem.value = money(itemTot);
     }else {
     elem.value = '';
     }
     orderTotNum = orderTotNum + itemTot
     var gt = document.getElementById('grandtotal');
     if(orderTotNum > 0){
             gt.value = money(orderTotNum);
     }else {
          gt.value = '';
     }
  }
}

The errors received are

[Error] SyntaxError: Unexpected token '<' (OLRform.js, line 23)
[Error] ReferenceError: Can't find variable: calculate
    onchange (OLRform.php, line 139)

where line 23 is the line declaring the optCount variable. I tried to enclose it in quotes to make the number a string, but that didn't help.

What did I miss?

[pritaeas]

Line 5 contains PHP, and will not be parsed if it is in a js file.

[NewHeart42108]

Thanks. Then there is no way to pass PHP variables to a separate .js file? Does that mean that all my JavaScript must be in the header of the HTML?

[pritaeas]

The only way to do that is to tell apache to parse the .js file, or rename the file to .php