Dependent Dropdowns (Linked Selects) with single class (no other selectors)

Question

I am trying to create multiple dependent dropdowns (selects) with a unique way. I want to restrict the use of selectors and want to achieve this by using a single class selectors on all SELECTs; by figuring out the SELECT that was changed by its index. Hence, the SELECT[i] that changed will change the SELECT[i+1] only (and not the previous ones like SELECT[i-1]).

For html like this:

<select class="someclass">
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="mercedes">Mercedes</option>
    <option value="audi">Audi</option>
</select>

<select class="someclass">
</select>

<select class="someclass">          
</select>

where the SELECTs other than the first one will get something via AJAX.

I see that the following Javascript gives me correct value of the correct SELECT and the value of i also corresponds to the correct SELECT.

$(function() {
    $(".someclass").each(function(i) {
        $(this).change(function(x) {
            alert($(this).val() + i);
        });
    });         
});

Please note that I really want the minimum selector approach. I just cannot wrap my head around on how to approach this. Should I use Arrays? Like store all the SELECTS in an Array first and then select those?

I believe that since the above code already passes the index i, there should be a way without Arrays also.

Thanks a bunch. AJ

UPDATE:

Here is somewhat better description:

1. There are more than 2 `SELECT`s on the page with class `someclass`. SELECT[0] has some values initially and its successors are empty as they will change based on the value of their respective immediate ancestor.
2. If there is a change in `SELECT[i]`, it fires an event and `SELECT[i+1]` is populated with appropriate `OPTION`s.
3. `SELECT[i+2]` and further successors are reset if they had any data before. So, only immediate child is populated but further successors are reset.

I hope I articulated well. Please let me know if you need more clarification on what I want.

Answer 1

Inside the change(), you can grab the next select element using the eq() function.

$('.someclass').eq(i + 1);

Alternatively (and better, I think), you can also use next() function.

$(this).next('.someclass');

Answer 2

EDIT: Corrected version.

$(function() {
    var $all = $('.someclass');              // Reference all the selects
    var last = $('.someClass').length - 1;   // Store index of last select

     $(".someclass").change(function() {

        var $th = $(this);           // Reference the changed select

        var index = $all.index($th);     // Grab the index of the changed select

        if(index != last) {              // If the selected wasn't the last,

            var $next = $all.eq(index + 1)      // reference the next select

            $all.filter(':gt(' + index + ')').empty(); // and empty all selects greater than the 
                                                       // index of the changed one.
                                                       // This will include the one that is about
                                                       //     to be populated.
                // Then presumably perform some AJAX
                //    based on $th.val(); to populate
                //    $next with options.
         }
    });         
});