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Shows the DebugBar for the web viewer on Windows.

Component Version macOS Windows Linux Server iOS SDK
WebView 10.3 ❌ No ✅ Yes ❌ No ❌ No ❌ No


This function was deprecated. Use WebView.ShowDevTools instead.

MBS( "WebView.ShowDebugBar"; WebViewerRef { ; Flags; X; Y; Width; Height } )   More


Parameter Description Example Flags
WebViewerRef Either the Web Viewer Object Name or the Web Viewer ID as returned by "WebView.FindByName" function.
Flags Various flags.
Add 1 to not scale for screens with >100%.
When window is scaled, it shows bigger, but may not have the picker work correclty.
Add 2 to put the window always on top of other windows.

Default is 0.
0 Optional
X The x position for placement on screen.
Default is near center of screen.
Y The y position for placement on screen.
Default is near center of screen.
Width The width of the window.
Default is 600.
600 Optional
Height The height of the window.
Default is 400.
400 Optional


Returns OK or error.


Shows the DebugBar for the web viewer on Windows.
With DebugBar you can inspect HTML elements, see scripts and modify elements on the fly.
There is a JavaScript console to quickly edit something if needed.

Please download and install DebugBar extension for Internet Explorer:

You may need to buy a license for it to use all features.

Known issues:
  • The toolbar has a gear button, where you can pick locations. Choosing a location there may crash FileMaker.
  • If FileMaker runs on a screen with >100% scaling, the picker may not work correctly unless you pass 1 for Flags parameter, but then icons may be smaller.
  • HTTPs tab shows no data.
  • You may need to click reload in the DebugBar (orange arrow in toolbar) when switching to another page.
  • Running JavaScript works, but doesn't show errors or results.
  • The inspect element in context menu command does not work.

For FileMaker 19.4 or newer in MBS Plugin 11.5 or newer, this will redirect to WebView.ShowDevTools function and show developer tools.


Show DebugBar:

# Show Debugbar in file WebViewer DebugBar

# Show debug bar if available
Set Variable [ $r ; Value: MBS("WebVIew.ShowDebugBar"; "web") ]
If [ MBS("IsError") ]
    Show Custom Dialog [ "Failed to show debug bar" ; $r ]
End If

See also

Release notes

Blog Entries

This function checks for a license.

Created 2nd July 2020, last changed 27th June 2022

WebView.SetUsePrivateBrowsing - WebView.ShowDevTools