Refresh/reload active browser tab from command line?

I'm trying to set up a custom toolchain where the browser (Firefox or, preferrably, Chrome) is often/frequently/constantly forced to refresh from the commandline.

(The idea is to instantly see the visual changes in the html/webapp I'm editing in an adjacent Emacs frame - without having to constantly tab to the browser to do a manual refresh.)

The closest I've come so far is to run google-chrome FILE_PATH. However this opens a new tab every time.

Are there other approaches?