Getting a variable from my form to my parser file via ajax

Question

I'm a total AJAX noob, so please forgive me, but this is what I'm trying to do... I have a php form that submits the information via ajax to a parser file. I need to get a few ids from that form to the parser file so I can use them in my sql update. I'll try to keep my code simple but give enough info so someone can answer.

My form is being generated via a foreach loop that iterates through a list of teams and grabs their various characteristics. For simplicity, let's say the main thing I need to get to the parser file is that team_id.

I'm not sure if I need to add

<input type="hidden" name="team_id" value="<?=$team->id ?>">

or

<tr data-teamid="<?=$team->id; ?>">

or something like that to my form....but either way, it gets passed through this AJAX file...

<script type="text/javascript">
     function updateNames() {
       jQuery('#form-message, #form-errors').html("");
       var post_data = jQuery('form[name="update_names"]').serialize();
       $.ajax({
         url: 'parsers/update_names.php',
         method: 'POST',
         data : post_data,
         success: function(resp) {
          if(resp == 'success'){
            jQuery('#form-message').html("Names and Scores have been Updated!");
           }else{
             jQuery('#form-errors').html(resp);
           }
         }
       });
       return false; // <--- important, prevents the link's href (hash in this example) from executing.
     }
     jQuery(document).ready(function() {
       $(".linkToClick").click(updateNames);
     });
   </script>

And is making it to my parser file, which looks like this...

require_once '../core/init.php';
 $db = DB::getInstance();
 $errors = [];

 // $camp_id = Input::get('camp_id');
 $camp_id = 18;
 //Find the Teams that Belong to the Camp
 $sql = "SELECT * FROM teams WHERE camp_id = $camp_id";
 $teamsQ = $db->query($sql);
 $all_teams = $teamsQ->results();

//validation and sanitization removed for simplicity.

if(empty($errors)){
  $fields = [];
  foreach($_POST as $k => $v){
    if($k != 'camp_id'){
      $fields[$k] = Input::get($k);
    }
  }

   $db->update('teams',$all_teams->id,$fields);
   echo 'success';
}else{
  echo display_errors($errors);
}

SO. The main question I have is how do I get that camp_id and team_id into the parser file so I can use them to update my database?

A secondary question is this...is the fact that the form is being generated by a foreach loop going to make it difficult for the ajax to know which field to update?

So, how would I get that camp_id to

 $sql = "SELECT * FROM teams WHERE camp_id = $camp_id";

And the team_id to

   $db->update('teams',$all_teams->id,$fields);

I tried to break this down to the simplest form and it's still not getting to the function. This code...

<form name="update_names" method="post">
<input type="hidden" name="team_id" value="<?=$teams->id ?>">
<button onclick="updateNames();return false;" class="btn btn-large btn-primary pull-right">test</button>

<script type="text/javascript">
     function updateNames() {
  alert('test');
     }
</script>

Gives me... Uncaught ReferenceError: updateNames is not defined

Answer 1

The jQuery .serialize() method uses the name attribute of an element to assign a variable name. It ignores the element's id, any classes and any other attribute. So, this is the correct format if using .serialize():

<input type="hidden" name="team_id" value="<?=$team->id ?>">

Looking at your ajax code, your parser file would be called parsers/update_names.php.

To verify that the desired field is getting to your parser file, add this to the top for a temporary test:

<?php
  $tid = $_POST['team_id'];
  echo 'Returning: ' .$tid;
  die();

and temporarily modify the ajax code block to:

$.ajax({
    url: 'parsers/update_names.php',
    method: 'POST',
    data : post_data,
    success: function(resp) {
        alert(resp);
    {
});
return false;

If the ajax processor file (your "parser") receives the team_id data, then you will get that data returned to you in an alert box.

Thus, you can now determine:

1. That you are receiving the team_id information;
2. That the ajax back-and-forth communications are working

Note that you also can install FirePHP and echo text to the browser's console from the php processor file.