Tracing is like executing, only it’s slower — slow enough that you can actually see the green arrow moving along the path of execution.

To trace:

• Choose Script > Trace.

• Or, click Trace in the toolbar.

The speed of tracing is determined by the trace speed slider. To see the trace speed slider:

• Choose Script > Trace. The slider is in the hierarchical menu (the Event Handler menu).

• Or, hold down Trace in the toolbar. The slider is in the pop-up menu (the Event Handler menu).

  This gesture can be a little finicky, because you have to get the Event Handler menu to remain open. Hold the mouse down in the Trace button in the toolbar, until the Event Handler menu appears. Still holding the mouse down, slide the pointer until it is over the menu. Now release the mouse. The Event Handler menu stays. Now you can manipulate the trace speed slider.

• Or, having customized the toolbar so that it includes the trace speed slider, use the slider in the toolbar.

The trace speed slider ranges between “tortoise” at the left and “hare” at the right.

Tracing is in one sense just a slower form of execution, and will pause for the same reasons (e.g., because a breakpoint is encountered, or because you issue the Pause command). However, what’s really happening is that Script Debugger is pausing and resuming after every executed line. This means that you can see more than the green arrow moving — you can also see the call stack growing and shrinking, and the variable values changing, and successive results appearing, just as you would if you if were repeatedly issuing the Step Into command.

Trace has the same options for executing handlers as Execute.