Disable / Deregister all JS from all plugins

You could install a plug-in like asset Queue Manager to keep track of all the active stylesheets and javascript files (it’s preaty neat, you can live-preview how the page would look without an asset to see if your site gets broken or not), and then in your theme’s functions.php file, put a code like the following

add_action( 'wp_print_scripts', 'my_deregister_javascript', 100 );
function my_deregister_javascript() {
  $deregistered_scripts=array('wc-add-to-cart',
    'woocommerce',
    'storefront-skip-link-focus-fix',
    'wc-add-to-cart-variation',
    'wc-cart-fragments',
    'storefront-navigation',
    'wc-single-product');
  foreach ($deregistered_scripts as $key => $script) {
    wp_deregister_script( $script );
  }
}

(of course you may want to replace the $deregistered_scripts array with only the ones that you won’t be using)

If your blog is in development mode and you find an error message after this, some plug-in might be causing the issue. Try adding an @ to the line 250 of /wp-includes/class.wp-scripts.php (it worked for me to solve an error warning woocommerce was throwing)

public function set_group( $handle, $recursion, $group = false ) {
        if ( @$this->registered[$handle]->args === 1 ) //"@" added
            $grp = 1;
        else
            $grp = (int) $this->get_data( $handle, 'group' );

        if ( false !== $group && $grp > $group )
            $grp = $group;

        return parent::set_group( $handle, $recursion, $grp );
    }

Edit: the deregistering-scripts code was addapted from this blog article by Justin Tadlock