Passing variable to external PHP file - php

Question

I'm having a (probably super simple) issue. The code below is supposed to _POST (using AJAX) a variable called 'id' to an external file called getYourData.php.
I think the issue is below. The 'data' section doen't seem to be functioning - I've even tried putting [data: '2'] to simply put '2' in the SELECT statement. But that doesn't even work.
$.ajax({
type: 'POST',
url: 'getYourData.php',
data: 'id',
success: function(msg){
//everything echoed in your PHP-File will be in the 'msg' variable:
$('#selectTwo').html(msg)
$('#selectTwo').fadeIn(500);
}
});
Here's the rest of code (snippet - jquery has been imported)
<!-- First Box: click on link shows up second box -->
<div id="selectOne" style="float: left; margin-right: 10px; border: #666 thin solid; padding: 10px;">
One<br />
Two<br />
Three
</div>
<!-- Second Box: initially hidden with CSS "display: none;" -->
<div id="selectTwo" style="float: left; margin-right: 10px; display: none; border: #666 thin solid; padding: 10px;"></div>
<!-- The JavaScript (jQuery) -->
<script type="text/javascript">
//Do something when the DOM is ready:
$(document).ready(function() {
//When a link in div with id "selectOne" is clicked, do something:
$('#selectOne a').click(function() {
//Fade in second box:
$('#selectTwo').fadeIn(500);
//Get id from clicked link:
var id = $(this).attr('id');
$.ajax({
type: 'POST',
url: 'getYourData.php',
data: '2',
success: function(msg){
//everything echoed in your PHP-File will be in the 'msg' variable:
$('#selectTwo').html(msg)
$('#selectTwo').fadeIn(500);
}
});
//Depending on the id of the link, do something:
if (id == 'one') {
//Insert html into the second box which was faded in before:
$('#selectTwo').html('One<br />is<br />selected')
} else if (id == 'two') {
$('#selectTwo').html('Two<br />is<br />selected')
} else if (id == 'three') {
$('#selectTwo').html('Three<br />is<br />selected')
}
});
});
</script>
getYourData.php - creates a custom SELECT statement based on the 'id' passed from primary page. For some reason, this isn't working. Only works when I intentionally set a dud variable ($id2)
<?php
$username="primary";
$password="testpass";
$database="testdb";
mysql_connect(localhost,$username,$password) or die ('Unable to connect...');
mysql_select_db($database) or die('Error: '.mysql_error ());
//Intentionally creating a dud variable will create a good SELECT statement and work
$id2 = "3";
$id = $_POST['id'];
$query = mysql_query('SELECT * FROM members WHERE member_id='.$id);
$result = mysql_fetch_assoc($query);
//Now echo the results - they will be in the callback variable:
echo $result['firstname'].', '.$result['lastname'];
mysql_close();
?>

Answer 1

data in your AJAX function needs to be of the form 'id=xxx'. I see you have it in the variable id. Try data: 'id=' + id. Confusing I know.
The explanation here is that POST data should be of the form a=b,c=d,... et cetera. That way PHP will pick it up as a key/value pair in the $_POST dictionary. Now you have a variable id which you would like to send (value), and you also want this to be the name of the (key). Hence you would need to do data: 'id=' + id. If id=2, then that will evaluate to data: 'id=2', which is correct.
Ultimately, as #Stephen noted, it is better to use an Object for the data field, as it is arguably more elegant. data: {'id': id} should work as well, and you can add more variables in the future.

Answer 2

Have you tried data: {id: 2 } - object, not an array.

Answer 3

I believe the data in your ajax call is wrong. The php references $_POST['id'] in your call but the var ID is not sent.
from : http://api.jquery.com/jQuery.ajax/
dataObject, String
Data to be sent to the server. It is converted to a query string, if
not already a string. It's appended to the url for GET-requests. See
processData option to prevent this automatic processing. Object must
be Key/Value pairs. If value is an Array, jQuery serializes multiple
values with same key based on the value of the traditional setting
(described below).
Should be more like this:
data: "id=2",