Webview - is it possible to update only a portion of the view?

Question

In the Webview extensions guide (https://code.visualstudio.com/api/extension-guides/webview), it states that in order to update the view, one needs to set the entire view (via panel.webview.html). Is it possible to only update a portion of the view, without having to updating the entire view?

I'd like to have a timer running (setInterval()) and either have an element blink on/off, or change an element's color (maybe toggle back and forth between white and red).

If this were an HTML page, I would use a CSS selector to find the element, and then either a) change its visibility, or b) add and remove classes applied to the element, but I haven't found a means to access the elements which were rendered.