The best way to do this is to start with a template override. A template override is where you put your own custom template for a module into your templates directory, which then allows your customizations to stay even if you install a new version of the module.
Creating the template override:
- Go to your /templates/<YOUR_CURRENT_TEMPLATE_DIR>/
- Create the directory 'html' if it doesn't exist
- Create the sub-directory 'mod_jfbclogin' under 'html'. You should now have a directory /templates/<YOUR_CURRENT_TEMPLATE_DIR>/html/mod_jfbclogin/
- Copy the file /modules/jfbc_login/tmpl/default.php to your newly created directory
Now you have a copy of the original mod_jfbclogin template in your template override directory. You can modify this file however you want and it won't be erased if a new version of the module comes out (though you may need to update it).
Now, edit the new default.php file (in the html/mod_jfbclogin directory). Go to line 31, it starts with '<fb:login-button'. Add the following bold text to the line:
<fb:login-button
length="long" onlogin="javascript:fb_login_button_click();"></fb:login-button>
You can add any of the parameters from the following page to customize that button how you want.
<!-- m --><a class="postlink" href="
wiki.developers.facebook.com/index.php/Fb:login-button">
wiki.developers.facebook.com/ind ... gin-button