onchange event not working on javascript

I am trying to create a row in a table. In that row i have some input and select elements.

I want to add an onchange event to an select element.

I am trying to do so.. but not working (see the bolded code below)

Please help me.

// this addrowt() triggered when a button is clicked.
function addRowt()
{
  var table1 = document.getElementById('slist');
  var lastRow = table1.rows.length;
  var iteration = lastRow;
  var row = table1.insertRow(lastRow);


  // Song number
  var c1 = row.insertCell(0);
  var it='song' + iteration;
  var textNode = document.createTextNode(it);
  c1.appendChild(textNode);

  // song title
  var c2 = row.insertCell(1);
  var e2 = document.createElement('input');
  e2.type = 'text';
  e2.name = 'song_t' + iteration;
  e2.id+ 
 'song_t' + iteration;
  e2.size = 25;
  c2.appendChild(e2);


  // song title
    // cell creation    

    var c3 = row.insertCell(2);

    //select 1

    *  var e3s1 = document.createElement('select');
      e3s1.name = 'song_dt' + iteration + '1';
      e3s1.id = 'song_dt' + iteration + '1';
      e3s1.options[0] = new Option('MU 128kbps', 'MU 128kbps', true);
      e3s1.options[1] = new Option('SS 128kbps', 'SS 128kbps');
      e3s1.options[2] = new Option('MF 128kbps', 'MF 128kbps');
      e3s1.options[3] = new Option('RS 128kbps', 'RS 128kbps');
      e3s1.options[4] = new Option('--NA--', '');
      e3s1.options[5] = new Option('Other', 'Other');




       [B] // Here not working
      e3s1.onselect = function() { checkother(); };[/B]

// I DEFINED THE checkother(); function



      c3.appendChild(e3s1);

    window.alert("hai");

    // input for select 1

      var e3is1 = document.createElement('input');
      e3is1.type = 'text';
      e3is1.name = 'song_dtt' + iteration + '1';
      e3is1.id = 'song_dtt' + iteration + '1';
      e3is1.size = 20;
      e3is1.style.display='none';
      c3.appendChild(e3is1);


    // input 1

      var e3i1 = document.createElement('input');
      e3i1.type = 'text';
      e3i1.name = 'song_dl' + iteration + '1';
      e3i1.id = 'song_dl' + iteration + '1';
      e3i1.size = 25;
      c3.appendChild(e3i1);


    c3.innerHTML += "<br>";

    //select 2

      var e3s2 = document.createElement('select');
      e3s2.name = 'song_dt' + iteration + '2';
      e3s2.id = 'song_dt' + iteration + '2';
      e3s2.options[0] = new Option('MU 128kbps', 'MU 128kbps');
      e3s2.options[1] = new Option('SS 128kbps', 'SS 128kbps', true);
      e3s2.options[2] = new Option('MF 128kbps', 'MF 128kbps');
      e3s2.options[3] = new Option('RS 128kbps', 'RS 128kbps');
      e3s2.options[4] = new Option('--NA--', '');
      e3s2.options[5] = new Option('Other', 'Other');
      c3.appendChild(e3s2);

    // input 2

      var e3i2 = document.createElement('input');
      e3i2.type = 'text';
      e3i2.name = 'song_dl' + iteration + '2';
      e3i2.id = 'song_dl' + iteration + '2';
      e3i2.size = 25;
      c3.appendChild(e3i2);

    c3.innerHTML += "<br>";

    //select 3

      var e3s3 = document.createElement('select');
      e3s3.name = 'song_dt' + iteration + '3';
      e3s3.id = 'song_dt' + iteration + '3';
      e3s3.options[0] = new Option('MU 128kbps', 'MU 128kbps' );
      e3s3.options[1] = new Option('SS 128kbps', 'SS 128kbps' );
      e3s3.options[2] = new Option('MF 128kbps', 'MF 128kbps', true);
      e3s3.options[3] = new Option('RS 128kbps', 'RS 128kbps' );
      e3s3.options[4] = new Option('--NA--', '' );
      e3s3.options[5] = new Option('Other', 'Other' );
      c3.appendChild(e3s3);

    // input 3

      var e3i3 = document.createElement('input');
      e3i3.type = 'text';
      e3i3.name = 'song_dl' + iteration + '3';
      e3i3.id = 'song_dl' + iteration + '3';
      e3i3.size = 25;
      c3.appendChild(e3i3);


    c3.innerHTML += "<br>";

    //select 4

      var e3s4 = document.createElement('select');
      e3s4.name = 'song_dt' + iteration + '4';
      e3s4.id = 'song_dt' + iteration + '4';
      e3s4.options[0] = new Option('MU 128kbps', 'MU 128kbps');
      e3s4.options[1] = new Option('SS 128kbps', 'SS 128kbps');
      e3s4.options[2] = new Option('MF 128kbps', 'MF 128kbps');
      e3s4.options[3] = new Option('RS 128kbps', 'RS 128kbps', true);
      e3s4.options[4] = new Option('--NA--', '');
      e3s4.options[5] = new Option('Other', 'Other');
      c3.appendChild(e3s4);

    // input 4

      var e3i4 = document.createElement('input');
      e3i4.type = 'text';
      e3i4.name = 'song_dl' + iteration + '4';
      e3i4.id = 'song_dl' + iteration + '4';
      e3i4.size = 25;
      c3.appendChild(e3i4);




  // lyrics by
  var c4 = row.insertCell(3);
  var e4 = document.createElement('input');
  e4.type = 'text';
  e4.name = 'song_lr' + iteration;
  e4.id = 'song_lr' + iteration;
  e4.size = 25;
  c4.appendChild(e4);

  // singer
  var c5 = row.insertCell(4);
  var e5 = document.createElement('input');
  e5.type = 'text';
  e5.name = 'song_sr' + iteration;
  e5.id = 'song_sr' + iteration;
  e5.size = 25;
  c5.appendChild(e5);  

  e2.focus();

  var slno1 = document.getElementById('slno');
  slno1.value = parseInt(slno1.value) + 1;
}