Most browsers today either ship with a developer console built in or exploit plug-ins for this purpose. Saxon-CE's processor sends output to the console by exploiting the relatively standard methods supplied by the window.console object. These are: error, info, warn and log, corresponding to Saxon-CE's SEVERE, WARNING, INFO and [FINE|FINER] logLevel thresholds respectively.

Trace output from Saxon-CE is enabled when logLevel is set to FINEST, the output is serialized in XML form. Trace output uses the dirxml console method if available - otherwise it falls back to standard log output. If an exception occurs within the trace the XML content is logged as non well-formed XML text.

Note that trace output can be quite voluminous, and that tracing can have a significant effect on performance.