POST表单到url字符串查询

I was wondering how to POST a form to a string query url. I know how to post a form, however, my urls are using string queries, and i cannot seem to post to the page i require.

My page url is along the lines of: ... Main_Franchise_Details.php?Franchise=NYC

Using:

 ...  Main_Franchise_Details.php?Franchise=<?php echo $admin_Franchise?>

I have tried:

 <form id="myform " class="Form" method="post"  
 action="Main_Franchise_Details.php?Franchise=
 <?php echo $admin_Franchise?>" accept-charset="utf-8">

The page posts to Main_Franchise_Details.php, instead of

    Main_Franchise_Details.php?Franchise=NYC

, for instance I have looked online but cannot find anything, any sugguestions.

Form:
action="receiver.php?variable_B=Im_a_get_variable" accept-charset="utf-8"> (etc ...)

put in receiver.php:

 echo '<pre> POST VARS: '; 
 print_r($_POST);
 echo 'GET VARS: '; 
 print_r($_GET);

You'll see variable_B under $_GET and variable_A under $_POST. Note that you should url_encode() all $_GET vars before sending and url_decode() when you read them:

 action="receiver.php?variable_B=<?= urlencode('Im a GET var") 

and in receiver.php:

 $variable_B = urldecode($_GET['variable_B']);