Understanding "gel('sysparm_item_guid').value" in ServiceNow

If you've been working with ServiceNow client-side scripts, particularly around catalog items and order guides, you may have encountered the JavaScript snippet gel('sysparm_item_guid').value. While this code might look cryptic at first glance, it plays a crucial role in ServiceNow scripting. In this article, we'll clearly explain what this means, explore common usage scenarios, and guide you through potential issues you may encounter, especially within the Service Portal environment.

What Does "gel('sysparm_item_guid').value" Mean?

The gel function in ServiceNow scripts is essentially a shorthand for the standard JavaScript function document.getElementById(). The expression gel('sysparm_item_guid').value is commonly used in client-side scripting to retrieve the unique identifier (GUID) associated with the current catalog item when working within an order guide.

In other words, sysparm_item_guid references the unique identifier of the item currently being processed within a user's order guide request. It enables scripts to dynamically access or manipulate specific item details, such as validating user inputs, ensuring required attachments, or fetching related record details.

Common Usage Scenarios and Practical Examples

One typical scenario where this expression is utilized involves validation of form submissions, especially attachments. Suppose your requirement dictates that an attachment must be included with certain catalog items. A client-side validation script might look like the following:

In this example, the script checks whether an attachment has been provided for the current catalog item in the cart. If not, the submission is blocked, and an alert message prompts the user to attach the necessary document.

Troubleshooting Common Issues

While gel('sysparm_item_guid').value works smoothly in the standard ServiceNow user interface (UI16 or UI Builder), some users experience issues in the Service Portal. A common error encountered in the Service Portal is:

ReferenceError: gel is not defined

This happens because the Service Portal environment does not inherently recognize the gel function. The Service Portal primarily uses AngularJS and a different set of client-side scripting methods compared to the classic UI.

How to Fix the 'gel is not defined' Error in Service Portal

To resolve this issue, replace gel() with native JavaScript or AngularJS approaches when scripting specifically for Service Portal forms. For example, use:

Alternatively, AngularJS methods or ServiceNow-provided APIs designed explicitly for Service Portal scenarios can be leveraged.

Alternative Solutions

In environments where client-side scripting proves unreliable or insufficient, consider implementing server-side validation using ServiceNow's business rules or script includes. Server-side scripts offer robustness, especially for validation processes that must consistently execute regardless of the user interface.

Understanding and properly implementing the gel('sysparm_item_guid').value function is essential for efficient client-side scripting in ServiceNow, especially when dealing with order guides. However, keep in mind the differences between the traditional ServiceNow UI and the Service Portal environment.

If you're experiencing issues with gel in the Service Portal, use native JavaScript DOM manipulation or AngularJS techniques instead. When possible, also explore server-side scripting alternatives for critical validation tasks.

By following these insights and solutions, you can enhance your ServiceNow scripting practices, ensuring smoother user experiences and fewer technical roadblocks.