Why my combobox only work in first row

Why my combobox only work in first row


Why my combo only work in first row but in second row doesn't work ? 

Myscript :

$("#btnAddRow").on('click', function() {
var table = document.getElementById("myTable");
var lastRow = table.rows.length;
var row = table.insertRow(lastRow);
col1 = row.insertCell(0);
col2 = row.insertCell(1);
col3 = row.insertCell(2);
col4 = row.insertCell(3);
col5 = row.insertCell(4);
col6 = row.insertCell(5);
col7 = row.insertCell(6);
col8 = row.insertCell(7);
col1.innerHTML = "<select name='fselect' id='buah' style='width:55px'><select><?php include                         'cbBarang.php';?></select></select>";
col2.innerHTML = "<input name='fnmbrg[]'  id='b' type='text'   size='30'>";
col3.innerHTML = "<input name='fsatuan[]' id='c' type='text'   size='20'>";
col4.innerHTML = "<input name='fharga[]'  id='d' type='text'   size='10' readonly>";
col5.innerHTML = "<input name='fjumlah[]' id='e' type='text'   size='10'>";
col6.innerHTML = "<input name='ftotal[]'  id='f' type='text'   size='10' readonly>";
col7.innerHTML = "<button onClick='deleteRow()'>Delete</button>";
col8.innerHTML = "<input name='fkdbrg[]'  id='a' type='hidden'   size='10'>";
})

i combine with php script for get data from server but doesn't work in second row...Anyone can help ? thx