I have various checkboxes with the same name:
<input type="checkbox" name="convocati[]" value="A">A
<input type="checkbox" name="convocati[]" value="B">B
<input type="checkbox" name="convocati[]" value="C">C
<input type="checkbox" name="convocati[]" value="D">D
<select name="S1">
<option value=""></option>
</select>
<select name="S2">
<option value=""></option>
</select>
Every change status, I wish that in the two select there are only checked values. Example: If I check A and C, the 2 SELECT will be:
<select name="S1">
<option value=""></option>
<option value="A">A</option>
<option value="C">C</option>
</select>
<select name="S2">
<option value=""></option>
<option value="A">A</option>
<option value="C">C</option>
</select>
If I uncheck A and check D (So C remain):
<select name="S1">
<option value=""></option>
<option value="C">C</option>
<option value="D">D</option>
</select>
<select name="S2">
<option value=""></option>
<option value="C">C</option>
<option value="D">D</option>
</select>
and so on...