---
title: "JXL formula performance and error handling FAQ"
canonical: "https://support.appfire.com/space/SUPPORT/3371860859/JXL%20formula%20performance%20and%20error%20handling%20FAQ"
format: markdown
---
### Summary

This article provides answers to common questions regarding the performance, stability, and error-handling capabilities of JXL formulas (JFL and JFL Script). It explains why JXL formulas do not impact Jira backend performance and how to resolve issues if a script causes a browser to freeze.

### Use case 1: Performance and stability

**Does running complex JXL formulas or JFL scripts impact the performance or stability of the Jira platform?**  
No. JXL is an entirely client-side application. The formulas and scripts execute within the user's web browser, not on the Jira server. Because no processing occurs on the backend, there is no risk of impacting the underlying Jira platform's performance or stability, even if thousands of sheets contain complex or broken formulas. To summarize, the formula feature operates entirely within JXL. The Jira instance performance outside of JXL is not impacted at all**.**

### Use case 2: Error handling and user experience

**How does JXL handle scripts that contain errors or are invalid?**  
JXL includes several layers of error handling:

- **Formula composer validation**: The formula composer prevents users from saving invalid or erroneous formulas.
- **Error panel**: The composer dialog displays a dedicated error panel with specific details about why a script might fail.
- **Cell-level reporting**: If a runtime error occurs (for example, an error that only triggers due to specific data in an issue), the affected table cells display an error indicator.

### Use case 3: Long-running or runaway scripts

**What happens if a script enters an infinite loop or requires excessive computing power?**  
In the extremely unlikely event that a highly complex script (such as a complex regular expression) is executed, an individual user's web browser window might freeze. This does not affect other users or the Jira environment.

To resolve a frozen browser window due to a formula:

1. Navigate to the URL of the affected sheet.
2. Append `?safeMode` to the end of the URL (or `&safeMode` if other parameters already exist).
3. Reload the page. The sheet loads without executing any formulas.
4. In the *Sheet* view, modify or remove the formula causing the issue.