GlideForm.getUniqueValue() — ServiceNow API

g_form.getUniqueValue()→ string

beginnerTested on Xanadu

What It Does

The getUniqueValue() method retrieves the sys_id of the record currently loaded in the form. This is the primary key that uniquely identifies the record in the database table. The method directly accesses the form's internal record identifier without making any server calls.

ServiceNow maintains this value in the client-side form context as part of the form's metadata. When a form loads, the platform automatically populates this identifier from the record's sys_id field. The method simply returns this cached value without any processing or validation.

For existing records, this method always returns a 32-character hexadecimal string representing the sys_id. For new records that haven't been saved yet, it returns either null or an empty string, depending on the browser and ServiceNow version. This inconsistency requires defensive coding when checking for new records.

The method behaves identically across all client-side contexts including Client Scripts, UI Policies, and UI Actions. However, the timing of when the sys_id becomes available differs. In onCreate scripts, the value is always empty since the record doesn't exist yet. In onChange and onSubmit scripts for existing records, the value is consistently available.

This method is closely related to g_form.getTableName() which returns the table name. Together, these two methods provide the complete record identifier (table + sys_id) needed for server-side operations like GlideAjax calls or building record URLs.

When to Use This

Use getUniqueValue() when you need to pass the current record's sys_id to server-side scripts via GlideAjax, build URLs to related records, or create reference field values. It's essential for any client-side logic that needs to identify the specific record being viewed or edited. Common scenarios include populating reference fields with the current record, building navigation links, or sending the record ID to custom REST endpoints.

Don't use this method when you need field values from the current record - use g_form.getValue() instead. Avoid using it in onCreate Client Scripts where you're checking if a record is new - use g_form.isNewRecord() for that purpose. Don't concatenate this value directly into URLs without proper encoding, especially in custom applications.

Return Value

Returns a string containing the 32-character sys_id for existing records. The format is always lowercase hexadecimal characters (0-9, a-f) in the pattern xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx. For new records that haven't been saved, returns either null or an empty string ''.

Always check for both null and empty string when testing for new records: !g_form.getUniqueValue() handles both cases reliably. The returned string is safe to use directly in GlideAjax parameters, URL construction, and database queries without additional encoding.

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Platform Behavior & Side Effects

No server-side code executes - this is purely a client-side data retrieval
No database queries are triggered - the value is cached in the form context
Performance is excellent - immediate return from memory with no network overhead
Works identically in all client script types (onLoad, onChange, onSubmit)
Value remains constant throughout the form session unless the record is saved for the first time
No ACL checks are performed - the sys_id is always accessible if the form loaded
Method execution is not logged in system logs or script tracer

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Code Examples

Basic usage — Getting current record ID for GlideAjaxbasic

function onLoad() {
    // Only proceed if this is an existing incident
    var currentSysId = g_form.getUniqueValue();
    if (!currentSysId) {
        return; // New record, nothing to do
    }
    
    // Pass the incident sys_id to a Script Include
    var ga = new GlideAjax('IncidentHelper');
    ga.addParam('sysparm_name', 'getRelatedProblems');
    ga.addParam('sysparm_incident_id', currentSysId);
    ga.getXML(function(response) {
        var answer = response.responseXML.documentElement.getAttribute('answer');
        if (answer) {
            g_form.addInfoMessage('Found ' + answer + ' related problems');
        }
    });
}

Shows the standard pattern for using the sys_id in Ajax calls. Always check for new records first to avoid sending null values to the server.

Intermediate — Building navigation URLs with proper null handlingintermediate

function onChange(control, oldValue, newValue, isLoading) {
    if (control == 'assigned_to' && !isLoading) {
        var incidentId = g_form.getUniqueValue();
        var assignedUser = g_form.getValue('assigned_to');
        
        if (incidentId && assignedUser) {
            // Build URL to user's other incidents
            var baseUrl = g_form.getParameter('sysparm_stack');
            var listUrl = '/incident_list.do?sysparm_query=assigned_to=' + assignedUser + 
                         '^active=true^sys_idNOT IN' + incidentId;
            
            var linkHtml = '<a href="' + listUrl + '" target="_blank">View other incidents for this user</a>';
            g_form.addInfoMessage(linkHtml);
        }
    }
}

Demonstrates building filtered list URLs that exclude the current record. The sys_id is used in the query to prevent showing the current incident in the list.

Advanced — The classic mistake with new record detectionadvanced

// WRONG - inconsistent behavior across browsers/versions
function onLoad() {
    if (g_form.getUniqueValue() == null) {
        // This won't catch empty strings!
        setupNewRecordLogic();
    }
}

// RIGHT - proper new record detection
function onLoad() {
    // Method 1: Use the dedicated method (preferred)
    if (g_form.isNewRecord()) {
        setupNewRecordLogic();
    }
    
    // Method 2: Handle both null and empty string
    if (!g_form.getUniqueValue()) {
        setupNewRecordLogic();
    }
}

The wrong approach only checks for null, missing empty string cases. Always use isNewRecord() or the truthiness check to handle both null and empty string returns reliably.

Gotchas

Returns either null or empty string for new records depending on browser and ServiceNow version - always use !g_form.getUniqueValue() to check for new records

The sys_id becomes available immediately after a new record is saved, but the form doesn't automatically refresh to show this change

Works in UI Actions but only if the action is configured to run client-side - server-side UI Actions don't have access to g_form methods

Value is cached when the form loads and won't change even if the record is modified in another browser tab or by another user

Method returns the sys_id even for records the current user might not have read access to in other contexts - the form loading implies permission

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