Programmatically clearing the Chart History is not a feature available in G Web Development Software at this time.
I was able to create a workaround using the JavaScript Library Interface to manipulate the Chart control directly. You can see an example in the Control Extensions for WebVI library with the Chart - History - Clear VI.
The usual warning applies when using a library to manipulate the NI provided controls directly:
If you use this library to modify the behavior of built-in controls, these modifications may not persist from release to release. Plan to test your code each time you upgrade to a new version of the G Web Development Software and update or modify this library as necessary. Alternatively you may consider integrating a 3rd party control where you have full control the behavior and upgrade timing.
Milan
