---
product: Chilkat
product_version: 11.7.0
language: wc
language_label: Unicode C
class: Js
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/wc_CkJsWRef.html
---
# Chilkat Js — Unicode C — v11.7.0

> Chilkat 11.7.0 · language=wc · class=Js
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/Js.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/wc/guide.md`.

## Purpose

**Execute sandboxed JavaScript inside an application with controlled access to Chilkat features.**

Use `Chilkat.Js` when an application needs to execute JavaScript internally while retaining control over what the script is allowed to access. By default, scripts run in a closed sandbox with the JavaScript language and standard library available, but without filesystem, network, or Chilkat class access unless the host application explicitly enables those capabilities.

**Embedded JavaScript engine**

Run JavaScript code from inside the host application without launching an external scripting process.

**Sandboxed by default**

Start from a restricted execution environment and selectively expose only the capabilities the script should use.

**Enable Chilkat classes**

Allow scripts to use selected Chilkat classes when the host application wants JavaScript to perform controlled Chilkat operations.

**Filesystem restrictions**

Optionally restrict filesystem access so scripts can read or write only within approved locations.

**Script input and output**

Execute JavaScript, pass data through the host-controlled environment, and retrieve results or diagnostics from the script run.

**Controlled automation**

Use JavaScript as an embedded extension language for application-defined workflows while keeping host resources protected.

**Common pattern:** Create a `Js` object, load or provide the JavaScript code, enable only the Chilkat classes and filesystem locations the script is permitted to use, run the script, and inspect the result or diagnostic output. Use `Chilkat.Js` when the application needs scriptability with a security boundary controlled by the host.

For an extended overview, see [Js Class Overview](https://www.chilkatsoft.com/js_class_overview.asp). Also see [About the Chilkat.Js JavaScript Engine](https://www.chilkatsoft.com/chilkat_javascript_engine.asp).

**Third-Party Notice** This software includes portions of the QuickJS JavaScript engine. Copyright © 2017–2024 Fabrice Bellard. Licensed under the MIT License. The Chilkat Js engine was originally derived from QuickJS, but has been extensively modified.

## Object creation, unlocking and error handling

**Create/Dispose**

```c
HCkJsW instance = CkJsW_Create();
// ...
CkJsW_Dispose(instance);
```

`HCkJsW CkJsW_Create(void);`

Creates an instance of the HCkJsW object and returns a handle ("void \*" pointer). The handle is passed in the 1st argument for the functions listed on this page.

`void CkJsW_Dispose(HCkJsW handle);`

Objects created by calling CkJsW_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkJsW_Dispose.

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in Unicode C.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `void CkJsW_getDebugLogFilePath(HCkJsW cHandle, HCkString retval); void CkJsW_putDebugLogFilePath(HCkJsW cHandle, const wchar_t *newVal); const wchar_t *CkJsW_debugLogFilePath(HCkJsW cHandle);` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastErrorHtml` | `void CkJsW_getLastErrorHtml(HCkJsW cHandle, HCkString retval); const wchar_t *CkJsW_lastErrorHtml(HCkJsW cHandle);` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `void CkJsW_getLastErrorText(HCkJsW cHandle, HCkString retval); const wchar_t *CkJsW_lastErrorText(HCkJsW cHandle);` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `void CkJsW_getLastErrorXml(HCkJsW cHandle, HCkString retval); const wchar_t *CkJsW_lastErrorXml(HCkJsW cHandle);` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `BOOL CkJsW_getLastMethodSuccess(HCkJsW cHandle); void CkJsW_putLastMethodSuccess(HCkJsW cHandle, BOOL newVal);` | read/write | Indicates the success or failure of the most recent method call: `TRUE` means success, `FALSE` means failure. |
| `VerboseLogging` | `BOOL CkJsW_getVerboseLogging(HCkJsW cHandle); void CkJsW_putVerboseLogging(HCkJsW cHandle, BOOL newVal);` | read/write | If set to `TRUE`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `void CkJsW_getVersion(HCkJsW cHandle, HCkString retval); const wchar_t *CkJsW_version(HCkJsW cHandle);` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `TimeoutSeconds` | property, read/write | `int CkJsW_getTimeoutSeconds(HCkJsW cHandle); void CkJsW_putTimeoutSeconds(HCkJsW cHandle, int newVal);` |
| `CallFunction` | method | `BOOL CkJsW_CallFunction(HCkJsW cHandle, HCkJsonObjectW funcJson, HCkJsonObjectW resultJson);` |
| `ConsoleOutputSb` | method | `void CkJsW_ConsoleOutputSb(HCkJsW cHandle, HCkStringBuilderW sb);` |
| `Eval` | method | `BOOL CkJsW_Eval(HCkJsW cHandle, HCkStringBuilderW jscript, HCkJsonObjectW resultJson);` |
| `SetCkPermission` | method | `BOOL CkJsW_SetCkPermission(HCkJsW cHandle, const wchar_t *chilkatClassName, const wchar_t *permission);` |

## Properties

### Js.TimeoutSeconds

`Chilkat 11.7.0 · wc · Js · TimeoutSeconds · property · read/write · since 11.4.0`

```c
int CkJsW_getTimeoutSeconds(HCkJsW cHandle);
void CkJsW_putTimeoutSeconds(HCkJsW cHandle, int newVal);
```

Specify a timeout in seconds to prevent JavaScript from running indefinitely, such as in an infinite loop. By default, the value is 0, meaning no timeout is set and infinite loops will continue forever.

## Methods

### Js.CallFunction

`Chilkat 11.7.0 · wc · Js · CallFunction · method · since 11.4.0`

```c
BOOL CkJsW_CallFunction(HCkJsW cHandle, HCkJsonObjectW funcJson, HCkJsonObjectW resultJson);
```

Calls a JavaScript function. The function name and arguments are passed in `funcJson`. The result is returned in `resultJson`.

Returns TRUE for success, FALSE for failure.

Async variant: `CallFunctionAsync` — same arguments, returns a `Task` (see Async variants below).

### Js.ConsoleOutputSb

`Chilkat 11.7.0 · wc · Js · ConsoleOutputSb · method · since 11.4.0`

```c
void CkJsW_ConsoleOutputSb(HCkJsW cHandle, HCkStringBuilderW sb);
```

Returns the console output in `sb` from the last call to `Eval` .

### Js.Eval

`Chilkat 11.7.0 · wc · Js · Eval · method · since 11.4.0`

```c
BOOL CkJsW_Eval(HCkJsW cHandle, HCkStringBuilderW jscript, HCkJsonObjectW resultJson);
```

Run `jscript` as a script. Return output and errors in `resultJson`.

Returns TRUE for success, FALSE for failure.

Async variant: `EvalAsync` — same arguments, returns a `Task` (see Async variants below).

### Js.SetCkPermission

`Chilkat 11.7.0 · wc · Js · SetCkPermission · method · since 11.4.0`

```c
BOOL CkJsW_SetCkPermission(HCkJsW cHandle, const wchar_t *chilkatClassName, const wchar_t *permission);
```

Sets sandbox related permissions for Chilkat objects. The `chilkatClassName` is the name of the Chilkat class (case-insensitive), such as `Http`, `Rest`, `"MailMan"`, `"Ftp2"`, `"Ssh"`, etc. The `chilkatClassName` can also be set to `"all"` to apply the permission to all Chilkat classes.

Possible values for `permission` are:

- `disable` - Your JavaScript code is not allowed to create an instance of the Chilkat class. A JavaScript exception is thrown when trying to create a Chilkat object of a class that is disabled.
- `sandbox` - Objects for the Chilkat class can be instantiated in JavaScript, but they have no read or write access to the local filesystem.
- `readOnly` - Objects for the Chilkat class can be instantiated in JavaScript and have read-only access to the local filesystem.
- `writeOnly` - Objects for the Chilkat class can be instantiated in JavaScript and have write-only access to the local filesystem.
- `readWrite` - Objects for the Chilkat class can be instantiated in JavaScript and have read/write access to the local filesystem.

By default, all Chilkat classes are **disabled**. Your application must enable `"all"` or specific Chilkat classes before calling `Eval` or `CallFunction` .

Returns TRUE for success, FALSE for failure.

## Events and callbacks

This binding delivers progress information through callbacks (AbortCheck, PercentDone, ProgressInfo, TaskCompleted) rather than events. See `guide.md` for how to attach them in Unicode C.

## Async variants

Each returns a `Task` instead of the result and takes the same arguments as the synchronous method; run the task, wait for `Finished`, then read the result from the task. No new Async methods are added from 11.7.0 on.

```c
HCkTaskW CkJsW_CallFunctionAsync(HCkJsW cHandle, HCkJsonObjectW funcJson, HCkJsonObjectW resultJson);
HCkTaskW CkJsW_EvalAsync(HCkJsW cHandle, HCkStringBuilderW jscript, HCkJsonObjectW resultJson);
```

## Related classes

[`JsonObject`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/wc/classes/JsonObject.md), [`StringBuilder`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/wc/classes/StringBuilder.md)