Update Oct 2016: With the recent Gmail update, the code was edited to prevent the menu from showing in Gmail apps (which does not support interactivity).

There has been a lot of interest in mobile menus in email ever since Jerry Martinez came out with his hamburger collapsible menu. The technique required the use of a checkbox to trigger the display and hiding of the menu.

However, a limitation of using checkboxes is that certain email service providers namely MailChimp does not support form elements in email and will strip them when the email is sent. In the same vein, some modern mobile email clients, namely Outlook on iOS does not support form elements as well.

Here’s a collapsible navigation menu for email that uses the :checked selector when available and :hover when not.

Hover

An alternative to using checkboxes is the use of the :hover selector. Hover has wide support on both email service providers and modern email clients. However, in certain cases the hover implementation on some clients are less reliable and glitchy than using a checkbox – particularly on the Windows 8.1 and Outlook for iOS clients.

Hybrid

Here’s a hybrid menu implementation that will use the checkbox mechanism when available, and fallback to hover when not. This way the code can be used on ESPs that don’t support form elements – though in that case, only the hover mechanism will be present in the email.

Specifically, the :hover selector below can only become active when .nav-over is a direct descendent of #navcontainer. In the original markup, .nav-over’s parent is a label, so by default, the :hover selector will not fire. However if the label is removed by the ESP or email client, then the :hover selector is enabled.

Code

View a live example here.

Here’s the code:
(Note -webkit-min-device-pixel-ratio was added to the media query filter to prevent it from appearing in Gmail after the updates)

Feedback

I’d love to hear your experiements with navigation menus and what other quirks you have encountered while using them.