chrome undo the action of "prevent this page from creating additional dialogs"

Close the tab of the page you disabled alerts. Re-open the page in a new tab. The setting only lasts for the session, so alerts will be re-enabled once the new session begins in the new tab.

No. But you should really use console.log() instead of alert() for debugging.

In Chrome it even has the advantage of being able to print out entire objects (not just toString()).

2 more solutions I had luck with when neither tab close + reopening the page in another tab nor closing all tabs in Chrome (and the browser) then restarting it didn't work:

1) I fixed it on my machine by closing the tab, force-closing Chrome, & restarting the browser without restoring tabs (Note: on a computer running CentOS Linux).

2) My boss (also on CentOS) had the same issue (alerts are a big part of my company's Javascript debugging process for numerous reasons e.g. legacy), but my 1st method didn't work for him. However, I managed to fix it for him with the following process:

• a) Make an empty text file called FixChrome.sh, and paste in the following bash script:

  #! /bin/bash
  cd ~/.config/google-chrome/Default     //adjust for your Chrome install location
  rm Preferences
  rm 'Current Session'
  rm 'Current Tabs'
  rm 'Last Session'
  rm 'Last Tabs'
  

• b) close Chrome, then open Terminal and run the script (bash FixChrome.sh).

It worked for him. Downside is that you lose all tabs from your current & previous session, but it's worth it if this matters to you.

So the correct answer is: YES, there is a better way.

Right click on the tab and select "Duplicate", then close the original tab if you wish.

Alerting is re-enabled in the duplicate.

The duplicate tab seems to recreate the running state of the original tab so you can just continue where you were.