======================
Breaking on exceptions
======================

To instruct the debugger to pause on an `exception <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error>`_, tick these checkboxes in the :ref:`Breakpoints list <debugger-ui-tour-breakpoints-list>`:


- Pause on exceptions
- Pause on caught exceptions


.. image:: version64ui.png
  :alt: Screen shot showing "Pause on exceptions
  :class: center

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 IceCat 80, a disclosure triangle within the tooltip reveals a stack trace.

.. image:: exception-tooltip-stacktrace.png
  :alt: Screenshot of a tooltip for an exception
  :class: center
