Managing client-side errors

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 error, a web development toolbar is required. ServiceNow recommends using Firebug. Firebug produces debugging information and indicates when the user has encountered an error. It integrates with Firefox to edit, debug, and monitor CSS, HTML, and JavaScript.

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 toolbar. Firebug is one of the most popular web development tools. Therefore, it is used to illustrate the following steps.

To debug a client script:

1. Using Firefox, navigate to the form where the issue is encountered. For example, Incident [incident].

1. Open Firebug and navigate to the Console tab.

1. Refresh the form.

1. 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.

   

1. 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.

1. 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.

For More information about how to use the various major browser debugger tools see the following websites:

• How to use Internet Explorer F12 Developer Tools to Debug your Webpages
• How to use FireFox FireBug to Debug your Webpages
• How to use Chrome Developer Tools to Debug your Webpages (Same tool is used for Safari)