Mobile Menu Button

Your theme’s JavaScript file isn’t being loaded: https://www.selectdomains.net/wp-content/themes/twentytwelve/js/navigation.js

Have you modified the theme’s files?

I have made modifications to the header to include a search bar.

How can I remedy this issue?

Ensure that the ‘twentytwelve_scripts_styles’ function is being called as per the original functions.php file: https://themes.svn.www.ads-software.com/twentytwelve/2.1/functions.php

I am having the same issue with Twenty Twelve Version 2.2. My site is theswampdrainers.org It works fine on everything but phones. There, the menu button appears, responds to a touch but nothing happens.