Managing client-side errorsIssue If a form displays unexpected behavior, there may be a problem on the client-side. ServiceNow tries to process all scripts loaded on an instance. However, there are multiple variations of scripts that can be loaded on a page and no software is completely immune to interference from others. Symptoms may include, but are not limited to: Client scripts or UI policies do not behave as expected or stop running.UI actions do not execute correctly when selected.A field or element on the form does not appear correctly. For example, cascade menus do not run or parts of a form do not load.Other JavaScript features suddenly stop working. Client-side issues are commonly caused by JavaScript errors. JavaScript errors can be a script or policy that prevents a form from loading correctly, a syntax error within a client-based script, or a reference to a non-existent element. To debug client-side errors, a web development toolbar is required. Most modern browsers include a similar tool by default. These tools provide ways to debug information and indicate when the user has encountered an error. They integrate with the browser to edit, debug, and monitor CSS, HTML, and JavaScript. Find out more in the Additional Information section at the end of this article. Procedure The resolution to a client-side error is always to fix the script causing the error. This involves identifying which component is causing the error. Since forms can get complex, there is no collective solution. The following steps help determine the source of the issue and how to resolve it using a web developer toolset. Note: The following screenshots are provided as support for the described steps and may be different than what you see, depending on the browser you use. To debug a client script: Navigate to the form where the issue is encountered. For example, Incident [incident].Open your browser's Developer tools and navigate to the Console tab.Refresh the form.Review the console for JavaScript errors and use them to investigate scripts that are running on the form. If the error references <table name>.do, it is probable the client-side error is generated from a client script written for a table. Click the <table name>.do link for further details on the error. Alternatively, right-click the form header and select Personalize > All form the context menu to display relevant scripts and policies. After the necessary changes, click Update and test the form to verify the issue no longer exists. If issue continues to exist, create an incident and include the error from the web developer debugger.Related LinksFor More information about how to use the various major browser debugger tools see the following websites: Google Chrome DevToolsMicrosoft Edge DevToolsFirefox Developer toolsApple Safari Developer tools