How to terminate script execution when debugging in Google Chrome?
Pressing “Reload this page” runs the rest of the code and even submits forms as if pressing F8 “Continue”.
When pressing F5 (Refresh) while a script is paused:
Google Chrome (v22) runs the script. If the script submits HTTP request, the HTTP response for that request is displayed. The original page is not refreshed.
IE 9 just freezes. However IE has an option “Stop Debugging” which, when pressed (provided you did not press F5 earlier), continues to run the script outside debugger.
Firebug behaves identically to Chrome.
Closing and then opening again the browser window is not always the next easiest way
because it will kill browser session state and that may be important. All your breakpoints are also lost.
UPDATE (Jan 2014):
Refresh while debugging:
Chrome v31: lets scripts to run and stops on further breakpoints (but does not submit ajax requests), then refreshes.
IE 11: refresh does nothing, but you can press F5 to continue.
Firefox v26: lets scripts to run but does not stop on further breakpoints, submits ajax requests, then refreshes.
Kind of progress!
Navigate to the same page while debugging:
Chrome v31: same as Refresh.
IE 11: scripts are terminated, new browser session is started (same as closing and opening again).
Firefox v26: nothing happens.
Also juacala suggested an effective workaround. For example, if you are using jQuery, running delete $ from console will stop execution once any jQuery method is encountered. I have tested it in all above browsers and can confirm it is working.
UPDATE (Mar 2015):
Finally, after over 2 years and almost 10K views, the right answer was given by Alexander K. Google Chrome has its own Task Manager which can kill a tab process without closing the tab itself, keeping all the breakpoints and other stuff intact.
I even went as far as BrowserStack.com to test it in Chrome v22 and found that this was working this way even at that time.
Juacala’s workaround is still useful when debugging in IE or Firefox.
UPDATE (Jan 2019):
Chrome Dev Tools at last added a proper way to stop script execution which is nice (although a bit hidden). Refer to James Gentes’s answer for details.
In Chrome, there is “Task Manager”, accessible via Shift+ESC or through
Menu → More Tools → Task Manager
You can select your page task and end it by pressing “End Process” button.
- Open the Sources panel.
- Click Pause. The button changes to Resume Script Execution.
One way you can do it is pause the script, look at what code follows where you are currently stopped, e.g.:
var something = somethingElse.blah;
In the console, do the following:
Then play the script: it will cause a fatal error when it tries to access
somethingElse, and the script will die. Voila, you’ve terminated the script.
...in upper right
Good thing is you can stop and rerun again just by checking/unchecking it.
If you want to prevent the rest of the script from being executed (e.g. due to AJAX calls that are going to be made) the only thing you can do is to remove that code in the console on-the-fly, thus preventing those calls from being executed, then you could execute the remaining code without problems.
I hope this helps!
P.S: I tried to find out an option for terminating the execution in some tutorials / guides like the following ones, but couldn’t find it. As I said before, probably there is no such option.
If you are encountering this while using the
… then I think the page will continue running forever until the js runtime yields, or the next break. Assuming you’re in break-on-error mode (the pause-icon toggle), you can ensure a break happens by instead doing something like:
or maybe call a non-existent function:
(Of course this doesn’t help if you are trying to step through functions, though perhaps you could dynamically add in a
throw 1 or
z() or somesuch in the Sources panel, ctrl-S to save, and then ctrl-R to refresh… this may however skip one breakpoint, but may work if you’re in a loop.)
If you are doing a loop and expect to trigger the
debugger statement again, you could just type
throw 1 instead.
Then when you hit ctrl-R, the next throw will be hit, and the page will refresh.
(tested with Chrome v38, circa Apr 2017)