Breaking on exceptionsΒΆ

To instruct the debugger to pause on an exception, tick these checkboxes in the Breakpoints list:

  • Pause on exceptions

  • Pause on caught exceptions

Screen shot showing "Pause on exceptions

When an exception occurs, the line where it occurs is highlighted in the source pane, with a squiggly red line under the problematic code. A tooltip describes the exception. Starting in Firefox 80, a disclosure triangle within the tooltip reveals a stack trace.

Screenshot of a tooltip for an exception