KB274712: "A script on this page may be busy, or it may have stopped responding." error appears when rendering documents or dashboards in Firefox in MicroStrategy Web 9.x and 10.x

SYMPTOM:
In Strategy Web 9.x or 10.x, when a large document or dashboard has finished executing in the Strategy Intelligence Server and begins rendering in Firefox, after some time the pop-up shown below appears:
 

Warning: Unresponsive script
A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete. 
Script: https://<web server name>/MicroStrategy/javascript/libraries/html2canvas.js?v=-2018184671:2842

 
Other browsers such as Internet Explorer and Chrome will use a similar but different message. 
CAUSE:
These warnings are to inform the user that a script is running over a predefined amount of time. In some cases, it may indicate issues such as memory leaks, page hangs, or malware. However, in the case of long rendering times of Strategy Web documents or dashboards that are particularly large or complex, this only means that the browser is currently running low on memory and needs more time to finish rendering. The memory allocation for the browser is dependent on the resources of the client machine and not of the web server machine, thus it cannot be controlled, or is not affected, by Strategy software. 
ACTION:
It is possible to disable these warnings via two methods:
 

1. Before the user hits "Continue" on the pop-up, there is an option to not show the warning again. However, this is per script and may not fully resolve the issue.
2. In Firefox, it is possible to increase the time to trigger the warning. 

Because this is a browser memory resources problem, the only solution available from the Strategy side to resolve this issue is to apply incremental fetch settings whenever possible, and reduce the complexity of the document. Both of those options can help to keep the rendering time down. For more information refer to tech note TN19625.
 
Third Party Software Installation WARNING:
The third-party product(s) discussed in this technical note is manufactured by vendors independent of Strategy. Strategy makes no warranty, express, implied or otherwise, regarding this product, including its performance or reliability.