How to link to live chat TawkTo module pop up window with Drupal 7?
You can easily achieve this by using Void Menu module.


Download &amp; Install Void Menu module.
Go to http://www.yoursite.com/admin/config/user-interface/void_menu 
Set javascript:void(Tawk_API.toggle()) as value for HTML value for &lt;void2&gt;
Then go to main menu configuration and set menu Path as &lt;void2&gt;