Edge/IE cookie limits
The June 1018 Cumulative Updates increased the per-domain cookie limit from 50 to 180 for IE and Edge across Windows 7, Windows 8.1, and Windows 10 (TH1 to RS2). This higher limit matches Chrome’s cookie jar.
In IE/Edge, if the cookie length exceeds 10240 characters, document.cookie returns an empty string. (Cookies over 1023 characters can also lead to an empty document.cookie string in the event of a race condition). Cookie strings longer than 10KB will still be sent to the server in the Cookie request header, although many servers will reject headers over 16kb in size.
In IE/Edge, the browser will ignore attempts to set (and suppress attempts to send) individual cookies (`name=value`) over 5118 characters in length.
At the time of this writing, there’s a nice test page that attempts to exercise cookie limits using the DOM.