Populate the dropdown based on another input for multiple fields

Question

I want to fetch the dropdown value based on an another input value and also i create the dropdown dynmaically using add button. how can i get the value appropriate.

Select rack name -> want to fetch the droplist of rack series using add button i must want to create many fields like this

Thanks in Advance, Please anybody give the solution for this.

function get_rack_series() {
    var rack = document.getElementsByClassName('rack');
    for (i = 0; i < rack.length; i++) {
        $.post(base_url+'suggest/get_rack_series',
            {
                rack_name:rack[i].value
            },
            function(res){
                $('.rs').html(res);
            }
        );
    }
}

This for add function
$(function() {
    var addDiv = $('#addinput');
    var i = $('#addinput p').size() + 1;

    $('#addNew').live('click', function() {
        $('<p><select name="rack[]" id="rack'+i+'" class="rack select_small caps_txt  validate[required]" onchange="get_rack_series();"><option value="">select</option><?php if(isset($get_rack_name)){foreach($get_rack_name as $rck){?> <option value="<?php echo $rck['rack_name'];?>"><?php echo $rck['rack_name'];?></option><?php }}?></select>&nbsp;<span id="rs" class="rs"></span>&nbsp;<input type="text" id="partnumber_' + i +'" name="partnumber[]" type="text" class="input4 validate[required] caps_txt" onblur="get_exists_status();"/><a href="#" id="remNew">Remove</a> </p>').appendTo(addDiv);
    i++;

        return false;
    });

    $('#remNew').live('click', function() {
        if( i > 1 ) {
            $(this).parents('p').remove();
            i--;
        }
        return false;
    });
});

html code

<td width="263">
    <div id="addinput">
        <p>
            <select name="rack_name[]" id="rack_name1" class="rack select_small caps_txt validate[required]" onchange="get_rack_series();">
                <option value="">select</option>
                    <?php
                        if(isset($get_rack_name)) {
                            foreach($get_rack_name as $rck)
                            {?>
                <option value="<?php echo $rck['rack_name'];?>"><?php echo $rck['rack_name'];?></option>
                    <?php 
                            }
                        }
                    ?>
            </select>&nbsp;
            <span id="rs" class="rs"></span>&nbsp;
            <input name="partnumber[]" type="text" class="input4 validate[required] caps_txt" id="partnumber" onblur="get_exists_status();" />
        </p>
    </div>
</td>

Answer 1

I would say echo all your options and add classes to them of the rack name, then hide and show them onchange .

Trying to hide some options tag with jquery doesn't work IE, Safari and Opera