In this case there is no need for a null check. Removing the list is not necessarily the use case I'm thinking about here.
What if a markup error is introduced to the HTML that causes the browser to parse it incorrectly, and the list isn't in the DOM?
What if someone opens the DOM inspector for the browser, and deletes the element?
Well, I guess you shouldn't do that.
I'm willing to bet that defect is what should get fixed, without spending additional time on null checks and error handling for a web page.
Basically, if for some odd reason the list disappears from the screen and you get a null reference error, will the absence of null checks make it harder to debug the problem, and if so, will be it hard enough to justify the extra code?
If it is still easy to debug, then no need for null checks.
If it is harder to debug, but not so hard it makes sense to spend time on this sort of error handling, then there is no need for null checks.
If, on the other hand, you are writing software that controls a robot arm, and a null reference exception causes it to swing around wildly while grasping a car door, then I'd say you better be putting some null checks in there.
But for a web page? Nope. Not worth the time (unless it makes web API calls to control a robot arm grasping a car door, of course. Also I hope you have really good authentication around this web API...).