Debugging - HTML5, JavaScript, and jQuery - page 144

Another very useful feature of the debugger is the pause button at the bottom of the menu:
If you click this once it will turn blue. This will cause the debugger to automatically pause
on any exception - including handled exceptions.
If you click it once more it will turn purple. This will cause the debugger to automatically
pause on all unhandled exceptions. This is very useful, since it is not always obvious that
a JavaScript error has occurred. As long as this setting is in place, and you always run the
application with the development tools open, you will not miss any errors, and will be able
to debug them while they are occurring.
In order to see this in action, remove the existing breakpoint, and change the code:
$('#btnAddTask').click(function(evt) {
evt.preventDefault();
$('#taskCreation').removeClass('not');
});
to
$('#btnAddTask').click(function(evt) {
evt.callUnknownFunction();
$('#taskCreation').removeClass('not');
});