In Google Chrome, you can pause execution without needing to place breakpoints.
Pause on Exception: While this button is toggled on, if your program hits an unhandled exception, the program will pause as if it had hit a breakpoint. The button can be found near Execution Controls and is useful for locating errors.
You can also pause execution when an HTML tag (DOM node) is modified, or when its attributes are changed. To do that, right click the DOM node on the Elements tab and select "Break on...".