获取选定的下拉值 - PHP

Question

I have a dropdown populated with values I get from the database. I need to perform some queries based on the selected option, but first I need to save the selected value on a new variable.

This is my dropdown:

<form name="dashboard_form" action="" id="dashboard_form" method="post">
    <tr>
     <td><?php _e('Select City')?>:</td>
     <td>
        <select class="selected_city" name="selected_city" style="margin: 20px;width:300px;" required>
        <?php
          foreach ( $all_cities as $city ) 
           {
            echo '<option value='.$city->ID.'>'.$city->name.'</option>';
           }
         ?>
        </select>
        </td>
     </tr>
</form>

*$all_cities is an array with all the cities.

My jQuery:

<script>
            jQuery("#dashboard_form").validate({
                ignore:'',
                rules: {
                    'selected_city': {
                     required: true
                }},
                messages: {
                    'selected_city': "Please Select a City",
                },
                errorPlacement: function(error, element) {
                    jQuery(element).closest('tr').next().find('.error_label').html(error);
                }
            });
</script>

How can I save on a $new_variable my selected value from the dropdown?

EDIT 1:

I added the following to

$(document).ready(function () {
    var selected_city;

    $('.selected_city').change(function() {
        selected_city = $(this).val();
        alert(selected_city);
    });
});

The alert(selected_city) prints the correct city, how can I use this selected_city on the PHP?

EDIT2: The problem is the dropdown is not submitting anything, so I created a Button to force it to Submit:

 <input type="submit" value="<?php _e('Send Now')?>" name="send_now_button" id="send_now_button" class="button button-primary">

Then:

if(isset($_POST['send_now_button'])){
        if(isset($_POST['selected_city'])) { $selected_city = $_POST['selected_city']; } else {$selected_city = 'Lisboa';  } }

Now when I echo $selected_cities_id; it gives the correct value!

Answer 1

Your HTML is invalid. <tr> can't be the child of <form>, it has to be the child or <table>, <tbody>, <thead>, or <tfoot>. This could be preventing the <select> from being treated as part of the form, so nothing is being submitted.

You need to put the form around the entire table.

<form name="dashboard_form" action="" id="dashboard_form" method="post">
    <table>
        ...
        <tr>
            <td><?php _e('Select City')?>:</td>
            <td>
                <select class="selected_city" name="selected_city" style="margin: 20px;width:300px;" required>
                <?php
                foreach ( $all_cities as $city ) 
                {
                    echo '<option value='.$city->ID.'>'.$city->name.'</option>';
                }
                ?>
                </select>
            </td>
        </tr>
        ...
    </table>
</form>