如何清除新行的数据？

I am adding new rows like this:

var table = document.getElementById('dataTable');
var rowCount = table.rows.length;
var row = table.insertRow(2);
var colCount = table.rows[3].cells.length;
for (var i = 0; i < colCount; i++) {
  var newcell = row.insertCell(i);
  newcell.innerHTML = able.rows[3].cells[i].innerHTML;
}

I don't want to loose input field data when refresh is done so, I use php session like these:

isset($_POST['details'])?$_SESSION['details'] = $_POST['details']:$_SESSION['details']="";

when I refresh and return same page session hold the previous data.
My problem is when i click add row button it generates same(previously inserted) data in new row also.

So I want to ask how to clear the data in new row. I think I need to have some code here:

for (var i = 0; i < colCount; i++) {

//need some code here to clear the field in newly created fields

  var newcell = row.insertCell(i);
  newcell.innerHTML = able.rows[3].cells[i].innerHTML;
}