Log

Logs have no impact on Workflows, their purpose is to help debug and understand your Workflows, and the results they create.

To use a Log action, it's simply connected to the end of a chain of Actions, or in the middle of a chain.

In the configuration panel, there is text field that you can type what to debug, for example, senderObject or another variable name. On the right side of the panel,the results will be displayed.
(Note : Results will only be displayed once the Workflow has been run in Preview mode.

The results are also displayed in the Issues & Logs panel, and if you use Mountain Lion, the results will also be displayed in the Notification Center.

Anything you debug must be valid JavaScript, so, for example, if you want to Log a message, then a value, the message must be quoted, and the value appended....

"This value should be zero:"+event.TheValue