#indent#function #selstart#MyFunctionName#selend#(row) {
  var qty = eval("document.forms['add'].elements['qty" + row + "'].value");
  var amt = eval("document.forms['add'].elements['amount" + row + "'].value");
  if(qty && amt){
    var total = (qty * amt);
    eval("document.forms['add'].elements['total" + row + "'].value = total");
  }
}

<body>

<form method="post" action="process.lasso" name="add">
[records]
<input type="text" name="[String_Concatenate:'amount',(LoopCount)]" value="[field:'amount']" size="4">
<input type="text" name="[String_Concatenate:'qty',(LoopCount)]" value="[field:'qty']" size="4" onchange="addline('[LoopCount]');">
<input type="text" name="[String_Concatenate:'total',(LoopCount)]" value="" size="4" onFocus="this.blur();">
[/records]
