JavaScript - añadir un select en una nueva fila de una tabla dinamica

<SCRIPT language="javascript">

          function addRow(tableID) {

	      var table = document.getElementById(tableID);

               var rowCount = table.rows.length;

               var row = table.insertRow(rowCount);

               var cell1 = row.insertCell(0);

               var element1 = document.createElement("input");

               element1.type = "checkbox";

               cell1.appendChild(element1);

               var cell2 = row.insertCell(1);

               var element2 = document.createElement("input");

               element2.type = "text";

		element2.name = "lab2";

		cell2.appendChild(element2);

		var cell3 = row.insertCell(1);

               var element3 = document.createElement("input");

               element3.type = "text";

		element3.name = "lab3";

		element3.size = "80";

		cell3.appendChild(element3);

          }

</SCRIPT>

var selector = document.createElement('select');

selector.id = 'Selector';

selector.name = 'Selector';

document.getElementById("miSelector").appendChild(selector);

var option = document.createElement('option');

option.value = '0';

option.appendChild(document.createTextNode('Selecciona...'));

selector.appendChild(option);

option = document.createElement('option');

option.value = '1';

option.appendChild(document.createTextNode('Coche'));

selector.appendChild(option);

option = document.createElement('option');

option.value = '2';

option.appendChild(document.createTextNode('Moto'));

selector.appendChild(option);