JAST supply a simple way to let your site interactive with the visitor. It's easy to use, but can still do complicate survey questionnaires.
JAST can be installed via the WordPress.org plugin directory. You can download the package from here, and upload the files to your server. Or you can open Plugins -> Add new menu in WordPress backend and search for "Just another survey tool" and install the first result item.
After activating JAST, you need add some css rules which can altered later to your theme's style.css to make the questionnaire show correct. You can do this by two ways:
Then you are able to improve your web site by supply professtional questionnaires.