// global counter (1 and 2 are hardcoded)
var next_sequence_number = 3;
var max_sequences = 5;

// create a new sequence field for the form
function more()
{
  if (next_sequence_number > max_sequences)
  {
    return;
  }

  // Get the <table> element
  var table = document.getElementById("input_table");

  // Make <tr></tr> block
  var tr = table.insertRow(table.rows.length);

  // Make <td>Sequence 3:</td>
  var td = tr.insertCell(tr.cells.length);
  var text = document.createTextNode("Sequence " + next_sequence_number + ":");
  td.appendChild(text);

  // Make <td><input name="SEQUENCE-3" size="80" value=""></td>
  var td = tr.insertCell(tr.cells.length);
  var input = document.createElement("textarea")
  input.setAttribute("name", "SEQUENCE_" + next_sequence_number);
  input.setAttribute("cols", "83");
  input.setAttribute("rows", "10");
  td.appendChild(input);

  next_sequence_number += 1;

  if (next_sequence_number > max_sequences)
  {
    var button = document.getElementById("more_button");
    button.disabled = true;
    var text = document.createTextNode("(Maximum of " + max_sequences + " sequences.)");
    button.parentNode.appendChild(text);
  }

}