php submit form and mod_rewrite

Hello friends, I have a question,

I use mod_rewrite in htaccess,

Options +FollowSymLinks
RewriteEngine On

RewriteRule ^([a-zA-Z0-9_-]+)$ index.php?do=search&subaction=search&story=$1
RewriteRule ^([a-zA-Z0-9_-]+)/$ index.php?do=search&subaction=search&story=$1


It means, normally the search page url is like

site.com/index.php?do=search&subaction=search&story=blabla

but I use mod_rewrite in htaccess and the above url can be seen by visiting this url:

site.com/blabla/

Everything is ok here. But if user search something from search form, the url is seen as

site.com/index.php?do=search&subaction=search&story=blabla

How can I make it the other type of url when user search something from search form? Thank you.

 

Redirect to site.com/blabla/

 

redirect the form action to the file with Search engine Friendly url

 

Use javascript which changes action url in the form according to the search field before submitting the form.