Duh! I have resolved the problem myself. How embarrassing that it only takes a simple step and not by editing, deleting the whole wp-includes/js directory, downloading the old version of WP and extract the file.. etc etc.. My visual/ text mode is back! After all the process that I’ve been through, by only clearing my browser cache, my problem was resolved. Sometimes it really takes a lot of mistakes and going back to simple solution to resolve the problem.