How to select value from dropdown without using submit

Question

I have two dropdowns: state and city. Both are in the same form. The goal is to somehow save the selection without clicking submit button so it could be used as a criteria to display selections of cities in the second dropdown. For example: When california is chosen in the first dropdown, second dropdwon displays all the cities in California.

Code:

<?php $db= DB::table('states_table')->get(); ?>
<select class="form-control input-md" name="state">
    <option value="" disabled selected>Choose the state</option>
    <?php foreach ($db as $data) { ?>
        <option value="<?php echo $data->city; ?>">
        <?php echo $data->city;?>
        </option><?php 
    }?>
</select>   

Answer 1

just use ajax :

    $('#form').on('change','select[name="state"]', function() {
    var province = $('select[name=state]').val();
    $.ajax({
        url: './get_city.php',
        method: 'post',
        data: {"state": state},
        success: function (data) {
            $('select[name=city]').html(data);
        }
    })
});

and in the get_city.php connect to db , get the cities and return them on tags

Answer 2

$('#state_field_id').click(function(){ var state=document.getElementById('state_field_name').options[document.getElementById('state_field_name').selectedIndex].text; });

你会得到选定的值