Question

I am trying to make two dependent select-boxes. There are two same select-boxes and the first selection hides the other one when it is selected, like this:

1st select-box
   Option one
   Option two (selected)
   Option three

2nd select-box
   Option one
   Option two (disappears)
   Option three

Answer 1

You can write something like this

<select id="s1">
    <option>1</option>
    <option>2</option>
    <option>3</option>
</select>
<select id="s2">
    <option>1</option>
    <option>2</option>
    <option>3</option>
</select>

and

$('#s1').change(function() {
    $('#s2').empty().append($('#s1 :not(:selected)').clone());
});

try it here http://fiddle.jshell.net/zDLMZ/
not optimal, but should work good on not big set of options