Metrics.NET | NET library provides a way of instrumenting applications | Analytics library

As per the docs, IE does not support the includes method. You can use indexOf instead:

Here I'll do it since he originally beat me by a couple seconds (I upvoted) and expand. Variables do not persist in the browser from session to session. you need cookies or localStorage for that.

HOWEVER, note there are differences between the two. If you are planning to support a wide variety of browsers and users, you'll need to check that local storage is available or else your user will be toast. If you are planning on sending this data ever back to the server, then cookies is still the preferred method if you really need it to persist.

I, like you, moved from ASP .Net into the web, and something to consider is, do you really need the front end to remember and store this data? For some things that is a security issue as well. Many times it can actually be preferable to pass the data you need back and forth, and when you are done it's disposed rather than physically caching it. I would argue in full web you should be polling for data every page load from the server even if it's redundant. That way you control what the user has, the front end is dumb, and you are sure the data is not tampered with which becomes very important...

I would say, tread lightly with storage outside of session tokens etc on the front end, it can get to be a mess very quickly and is very un-webby. How are you going to insure that the data is not stale, what if modifications are made? How long are you going to have the data persist without a refresh, when you get a large number of users, if they don't wipe their cache and you let them store something for x-length of time, you're going to run into this and it's a fundamental design flaw. Even if you refresh the data every few minutes, when you get to scale that is an eternity and you will get data conflicts. Decide if you really, really, really need this stored on the (and each) user's machine.

The link is only visible while the input field has :focus (i.e. when the user has clicked inside the input field). You need to tweak the css selector that is showing the results list to include :hover on the results list (so after the list is populated the user moves the mouse over the list the list is still visible when the user clicks off the input and onto the result) :