jQuery /any javascript in your page won't work if javscript is disabled in the browser. As javascript plays a major role in improving the user experience in today's web applications, I would definitly add a Message to the user if javascript is disabled.
<noscript>
<p>You are missing some awesome features of this site. Enable Javascript to see it</a>
</noscript>
If you really want to make it work without javascript, you may submit your form (the user should click on the submit button) after selecting the Country from the dropdown. Your POST action can read the selected country and get a list of States and set that in your Mode/ViewModel and send it back to the View again. But this is not a user friendly option !. So many button clicks and Form submits. AH !!! . I would tell the user to enable javascript.