Changing content using $_POST - php

Question

im trying to change the value of a field in $_POST so that it will load the correct content for whatever has been posted.
When a user goes onto my website $_POST is initially set as
$_POST['order_page_content'] = 'list'
I then have a form in my view.content.php file that looks like this:
<td><form action='http://localhost/magento_soap_client/fulfilment' method='POST'>
<input type='hidden' name='order_page_content' value='info'/>
<input type='hidden' name='order_id' value='$order_info->order_id'/>
<input type='submit' value='View'/>
</form></td></tr>";
So the value of $_POST['order_page_content'] should change to info when the button is clicked. Therefore the content of the page should change...
Once the button is clicked, i can see via firebug that the value has changed in the post, its just my page isn't getting set to it
So how do i make the content change based on the post value that got submitted? Or what is going wrong?
EDIT
Ok guys ive tried what you said, but its still not happening, i dont know if i have put it in the wrong place or what... i think the easiest way is to show you my code.
The script to decide which content it is is here:
link
and the script that calls it is here:
public function get_html() {
$m_html = null;
if($_POST['order_page_content'] == 'list'){
$m_obj_html = new content();
$m_html = $m_obj_html->get_page_content('list');
}
else if($_POST['order_page_content'] == 'info'){
$m_obj_html = new content();
$m_html = $m_obj_html->get_page_content('info');
}
return $m_html;
}
The post['order_page_content'] is getting set in the bootstrap initially to list
Thanks

Answer 1

<input type='hidden' name='order_id' value='<?php echo $order_info->order_id; ?>'/>
if it's already in php use
<input type='hidden' name='order_id' value='". $order_info->order_id ."'/>

Answer 2

$_POST is set globally from PHP.
If you have something in your script like:
$_POST['order_page_content'] = 'list';
So your variable is on each page load overwritten.
Try to check for it before you set it.
if (!array_key_exists('order_page_content', $_POST)
{
$_POST['order_page_content'] = 'list';
}

Answer 3

$_POST is set with post data sent from the client when they access the site. You can access it if they send any. Your form looks like it should work. What I do see though is that you make them send this against a page on the localhost. Is localhost running an apache or similar server with PHP? If it is, then on that page add this:
if(!empty($_POST['order_id'])){
print_r($_POST);
}
If that form is on the page you send them to, and you want the value to be remembered (still be there after they send in the form/post data, then do this:
<input type='hidden' name='order_id' value='<?php if(!empty($_POST['order_id'])) echo $_POST['order_id']; ?>' />

Answer 4

Tom You can check it with the use of if condition
if($_POST['order_page_content']=="info"){some code} else { some code}

Answer 5

Seems like the problem was this line:
<form action='http://localhost/magento_soap_client/fulfilment' method='POST'>
The url in action was resetting everything, so i have now taken it out and left action blank and works fine
Thanks for your help though guys