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Debugging a WebVI

Last Modified: November 16, 2020

Unlike desktop VIs, WebVIs do not currently support debugging tools, such as execution highlighting, probes, and breakpoints. However, you can still debug a WebVI using the following strategies.

Choose between the following debugging options.
Use Case Instructions

You want to see the error output of diagram objects.

WebVIs support an alternative to automatic error management that logs unhandled errors to the Output tab or browser development console. Because this does not provide the full capabilities of automatic error management, make sure you follow the guidelines for programmatic error management.

To view your error output, create an error indicator and place it on the panel.

Use this debugging strategy in either of the following cases.

  • You need to debug a subVI in your web application.
  • You want to log error information to the console of your web browser.

To write log error information to the console of your web browser or LabVIEW NXG output window, go to the diagram palette and select Interoperability»Operating System»Write to System Log.

To view the information output by Write to System Log within the editor, on the Navigation pane, open the Output tab by clicking Tool Launcher»All»Output.

To view the information output by Write to System Log in a web browser, use the console of the web browser development tools.

You need to debug your top-level WebVI.

Wire extra indicators at any point in your WebVI code to imitate probes and display the data that flows through a wire.


WebVIs do not currently support G types as controls or indicators on the panel. If you create an indicator from a G type on the diagram, no corresponding indicator is available on the panel.

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