Jquery Ajax将数据传递到另一个php文件来更新数据库只允许更新一次（Wordpress）

I am trying to redirect the data using POST method to a file in Wordpress called functions.php. It is able to send the data detected from the textbox to that file and gets the return value by using wp_send_json($_POST). After getting the returned value, the value of the paragraph was able to change to its new value. But it only allows me to update it once unless the page is being refreshed or reloaded. What have i done wrong or have i missed? Below are my codes for this process.

functions.php

function test_load(){
    if(isset($_POST) && $_POST['element'] == 'header')
    {
        $name = $_POST['name'];
        $hidden = $_POST['hidden'];

        if( $hidden == 'tagline')
        {
            update_option( 'wpbst_tagline', $name );
        }
        else if( $hidden == 'footer')
        {
            update_option( 'wpbst_footer', $name );
        }

        wp_send_json($_POST);
    }
}

add_action('init', 'test_load');

script

<script>

  $(document).ready(function(){

    function custom_update_box( id ) {

        $(id).click(function () {

          if(id == '#tagline')
          {
            var dynamicDialog = $('<div>\ <label>\ Tagline :\ </label>\  <input type="hidden" value="tagline" id="hidden">\ <input  id="update" class="form-control" type="textbox" value=\'' + $(this).html().trim() + '\'/>\ </div>');
            title = "Update Tagline";
          }
          else if(id == '#logo')
          {
            var dynamicDialog = $('<div>\ <label>\ Logo :\ </label>\  <input type="hidden" value="logo" id="hidden">\ <input id="update" class="form-control" type="textbox" value=\'' + $(this).html().trim() + '\'/>\ </div>');
            title = "Update Logo";
          }
          else if(id == '#footer')
          {
            var dynamicDialog = $('<div>\ <label>\ Logo :\ </label>\  <input type="hidden" value="footer" id="hidden">\ <input id="update" class="form-control" type="textbox" value=\'' + $(this).html().trim() + '\'/>\ </div>');
            title = "Update Footer";
          }

          dynamicDialog.dialog(
          { 
            title: title, 
            modal: true, 
            buttons: {
                'Submit': function(e) {
                  console.log(e);
                  $.ajax({
                    type: "POST",
                    data: { name: $("#update").val() , hidden: $("#hidden").val() , element: "header"}
                  }) 
                  .done(function(msg) {

                    console.log($("#update").val());

                    if(id == '#tagline')
                      $(id).html(msg.name);
                    else if(id == '#logo')
                      $(id).html(msg.name);
                    else if(id == '#footer')
                      $(id).html(msg.name);
                  });
                  $(this).dialog('close');
              },
                'Cancel': function() {
                $(this).dialog('close');
              }
            }

          });

      });

    }

    custom_update_box("#tagline");
    custom_update_box("#logo");
    custom_update_box("#footer");

  });

</script>

HTML

    <center>
      <span id="logo" class="bs-docs-booticon bs-docs-booticon-lg bs-docs-booticon-outline">
        <?php echo $logo_decode->wpbst_logo_initial; ?>
      </span>

        <td>
          <p id="tagline" name="blogdescription" class="lead"><?php echo $result_tagline;?></p>
          <input id="tagline" type="hidden" name='blogdescription' value=<?php echo '"'.$result_tagline.'"';?> />
        </td>

      <p class="lead">
        <a id="button" class="btn btn-outline-inverse btn-lg" href=""><?php echo $button_decode->wpbst_button_name;?></a>
      </p>
    </center>

I Have found a way, where I have removed the data from #update by adding the code inside the jquery ajax calling function:

success:function(data) {
    $('#update').remove();
}

The code above remove the data inside #update and it answered my problem. If ever there would be a better way, I would love to learn about it too. As for now, :D