Execute Javascript (Server)

Audience: Low-code Engineers

Skill Prerequisites: JavaScript, Tokens

Runs JavaScript code on the server and can store the result in a token. It uses the Google V8 engine through Microsoft ClearScript.

This is plain JavaScript, not a browser. There's no window, document, console, fetch or setTimeout. To run JavaScript in the user's browser, use Execute Javascript Code instead.

All tokens in the context are available in the script as variables. Your code runs inside a function, so use return to send a value back.

Typical Use Cases

• Reshape the JSON returned by a Server Request, for example to keep only a few fields
• Calculate values that are awkward to do with tokens or SQL, such as totals, discounts or date math
• Build a string, like a formatted address or a CSV line, from several tokens
• Call a simple HTTP endpoint with WebClient or XMLHttpRequest

Don't use it to

• Run code in the browser. Use Execute Javascript Code.
• Call a web service with headers, authentication or retries. Use Server Request.
• Turn a JSON string into tokens. Use Parse JSON Into Tokens or Create List from JSON.
• Run C# or .NET code. Use Execute Razor.

Related Actions

Action Name	Description
Execute Razor	Runs C# Razor code on the server.
Execute Javascript Code	Runs JavaScript in the user's browser.
Server Request	Calls a web service and stores the response.
Parse JSON Into Tokens	Turns a JSON string into tokens.
Execute Actions	Catches errors so execution can continue.

Input Parameter Reference

Parameter	Description	Supports Tokens	Default	Required
Script Name	A name that says what the script does. It's only a label and doesn't change how the script runs.	No	empty string	No
Local Variables	Extra variables for the script. Each row has a Type (string, int, double or bool), a Variable Name and a Variable Value. The name must be a valid identifier, like taxRate. The value can contain tokens and is converted to the chosen type.	Yes (Value only)	empty	No
Code	The JavaScript to run. Use return to send a value back. Tokens in square brackets aren't replaced here. Use the token's variable instead, for example Email rather than [Email].	No	empty string	Yes
Output Token	The token name that holds the value returned by the script, for example Result. See Returning Data.	No	empty string	No
On Error	Actions to run if the script fails. The error message is in the [ErrorMessage] token. See Errors.	No	empty	No

Output Parameters Reference

Parameter	Description
Output Token	Holds the value returned by the script. If an object is returned, each first-level property is also available as [Output Token:Property].

Available Variables

These variables are created automatically before the script runs. Names are case-sensitive, so use them exactly as they're defined.

Name	Description
Context tokens	Every token in the context, such as form fields, workflow inputs and tokens created by earlier actions. A token named Email is the variable Email.
Grouped tokens	Tokens with a colon in their name are grouped into one object. For example, [Guest:Username] and [Guest:VisitCount] become Guest.Username and Guest.VisitCount.
User	The current user.
Page	The page the actions were started from. It's empty when nothing started them from a page, for example in a scheduled job.
Module	The module that started the actions.
Portal	The current portal settings.
Token namespaces	Custom tokens, accessed as Namespace.TokenName, for example Company.SupportEmail. See Custom Tokens and Namespaces.
__Global	The same core objects and namespaces. Use it when a token or local variable has the same name, for example __Global.User.
Local Variables	The variables defined in the Local Variables parameter. They override context tokens with the same name.

Additional Objects

Besides the built-in JavaScript objects, the script can use these types:

Type	Description
WebClient	The .NET WebClient class, for simple HTTP calls.
XMLHttpRequest	A Windows MSXML2.XMLHTTP object. Use it synchronously.
DateTime	The .NET DateTime type. Use it to return dates.
DateTimeOffset	The .NET DateTimeOffset type, a date with a time zone offset.

A request with WebClient:

var client = new WebClient();
return client.DownloadString('https://example.com/api/status');

The same request with XMLHttpRequest:

var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://example.com/api/status', false);
xhr.send();
if (xhr.status != 200)
    throw new Error('Request failed: ' + xhr.status);
return xhr.responseText;

Returning Data

What's stored in the Output Token depends on what the script returns:

Script returns	Output Token
A string, number or boolean	The value, for example [Sum].
A DateTime or DateTimeOffset	The date.
An object with properties	Each first-level property as [Output:Property], and [Output] as the JSON of all of them.
Nothing, null or undefined	An empty value.
An array, a JavaScript Date or an empty object	The text Not supported.

For example, with Output Token set to Guest, this script creates [Guest:username], [Guest:visitCount] and [Guest]:

return {
    username: 'john',
    visitCount: 7,
    lastVisit: DateTime.Now
};

To return an array or nested data, convert it to a string with JSON.stringify. Then use an action like Create List from JSON to work with it.

Errors

If the script fails, for example because of a syntax error or a throw, this happens:

1. The error message is stored in [ErrorMessage].
2. The On Error actions run.
3. If an On Error action ends execution, like Stop Execution or Display Message, that's the result. Otherwise, the error is passed up and the module's error handling applies.

To handle the error and keep going with the next actions, put this action inside Execute Actions and use its On Error instead.

Considerations

• Licensing. This action needs the Scripting feature in your license.
• Server requirements. The server needs the Microsoft Visual C++ Redistributable for Visual Studio 2019 or later. Download it from Visual Studio Downloads. The IIS application pool must run as 64-bit.
• Tokens aren't replaced in Code. Use variables, not [Token] syntax. If you need a token value, you can also pass it through Local Variables.
• Case matters. email and Email are different variables.
• Local Variables are checked first. An invalid type, name or value stops the action with an error before the script runs. On Error doesn't run in that case.
• The script can't change tokens directly. Only the returned value comes back, through Output Token. Local Variables aren't kept after the action.
• Keep returned objects flat. Only first-level properties become tokens.

Examples

tip

To understand how to use the below examples, please see Running Examples.

1. Calculate an order total

This action uses the Quantity and UnitPrice tokens, and a tax rate from Local Variables. With Output Token set to Order, the results are [Order:Subtotal], [Order:Tax] and [Order:Total].

{
    "Title": "Execute Javascript (Server)",
    "ActionType": "ExecuteJavascript",
    "Description": "Calculate subtotal, tax and total",
    "Parameters": {
        "ScriptName": "Order total",
        "LocalVariables": [
            {
                "Type": "double",
                "Name": "taxRate",
                "Value": "0.08"
            }
        ],
        "Code": "var subtotal = Number(Quantity) * Number(UnitPrice);\nvar tax = Math.round(subtotal * taxRate * 100) / 100;\nreturn {\n    Subtotal: subtotal,\n    Tax: tax,\n    Total: subtotal + tax\n};",
        "OutputTokenName": "Order",
        "OnError": []
    }
}

2. Keep only a few fields from a JSON response

This action reads the ContactJSON token, for example the output of a Server Request. It keeps the first name, last name and email of each contact and returns them as a JSON string in [ContactList].

{
    "Title": "Execute Javascript (Server)",
    "ActionType": "ExecuteJavascript",
    "Description": "Simplify the contacts JSON",
    "Parameters": {
        "ScriptName": "Simplify contacts",
        "LocalVariables": [],
        "Code": "var data = JSON.parse(ContactJSON);\n\nvar contacts = data.contacts.map(function (contact) {\n    return {\n        firstname: contact.firstname,\n        lastname: contact.lastname,\n        email: contact.email\n    };\n});\n\nreturn JSON.stringify(contacts);",
        "OutputTokenName": "ContactList",
        "OnError": []
    }
}

3. Call an API and log failures

This action downloads a status page with WebClient and stores it in [ServiceStatus]. If the call fails, the error is logged and execution stops.

{
    "Title": "Execute Javascript (Server)",
    "ActionType": "ExecuteJavascript",
    "Description": "Check the service status",
    "Parameters": {
        "ScriptName": "Service status",
        "LocalVariables": [],
        "Code": "var client = new WebClient();\nreturn client.DownloadString('https://example.com/api/status');",
        "OutputTokenName": "ServiceStatus",
        "OnError": [
            {
                "Title": "Log Error",
                "ActionType": "LogError",
                "Parameters": {
                    "Message": "Status check failed: [ErrorMessage]"
                }
            },
            {
                "Title": "Stop Execution",
                "ActionType": "Result.StopExecution",
                "Parameters": {}
            }
        ]
    }
}

Revised 09/26/2026