can return 0 value? html code

i have a checkbox table.

<tr> <td height="30" align="center">x</td>

<td height="30" align="center">9-10</td>
     <td height="30" align="center">10-11</td>
     <td height="30" align="center">11-12</td>

</tr>

<tr>
  <td height="30" align="center"> y</td>

  <td height="30" align="center"><input type=checkbox name=composer value=1><br><br></td>
   <td height="30" align="center"><input type=checkbox name=composer value=2><br><br></td>
    <td height="30" align="center"><input type=checkbox name=composer value=3><br><br></td>

</tr>

</form>
</html>

i need to write all checked and unchecked checkbox values to text but i cant write unchecked checkbox values as zero value to text. if i select first and third checkbox, it should write 1,0,3 to text but this code writes 1,3

Dim fso,tst


Set fso=Server.CreateObject("Scripting.FileSystemObject")
Set tst = fso.OpenTextFile("C:\reading.txt", 2, true)

tst.writeline  Request.Form("composer")



tst.close
Set tst = Nothing
Set fso = Nothing