---
product: Chilkat
product_version: 11.7.0
language: objc
language_label: Objective-C
class: Js
class_name: CkoJs
license: bundle
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/objcCkoJsRef.html
---
# Chilkat Js — Objective-C — v11.7.0

> Chilkat 11.7.0 · language=objc · class=Js (CkoJs)
> 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/objc/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

**Object Creation**

```objectivec
CkoJs *obj = [[CkoJs alloc] init];
```

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 Objective-C.

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## 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` | `@property (nonatomic, copy) NSString *DebugLogFilePath;` | 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` | `@property (nonatomic, readonly, copy) NSString *LastErrorHtml;` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `@property (nonatomic, readonly, copy) NSString *LastErrorText;` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `@property (nonatomic, readonly, copy) NSString *LastErrorXml;` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `@property (nonatomic) BOOL LastMethodSuccess;` | read/write | Indicates the success or failure of the most recent method call: `YES` means success, `NO` means failure. |
| `VerboseLogging` | `@property (nonatomic) BOOL VerboseLogging;` | read/write | If set to `YES`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `@property (nonatomic, readonly, copy) NSString *Version;` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `TimeoutSeconds` | property, read/write | `@property (nonatomic, copy) NSNumber *TimeoutSeconds;` |
| `CallFunction` | method | `- (BOOL)CallFunction:(CkoJsonObject *)func     result:(CkoJsonObject *)result;` |
| `ConsoleOutputSb` | method | `- (void)ConsoleOutputSb:(CkoStringBuilder *)sb;` |
| `Eval` | method | `- (BOOL)Eval:(CkoStringBuilder *)jscript     result:(CkoJsonObject *)result;` |
| `SetCkPermission` | method | `- (BOOL)SetCkPermission:(NSString *)chilkatClassName     permission:(NSString *)permission;` |

## Properties

### Js.TimeoutSeconds

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

```objectivec
@property (nonatomic, copy) NSNumber *TimeoutSeconds;
```

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 · objc · Js · CallFunction · method · since 11.4.0`

```objectivec
- (BOOL)CallFunction:(CkoJsonObject *)func 
    result:(CkoJsonObject *)result;
```

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

Returns YES for success, NO for failure.

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

### Js.ConsoleOutputSb

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

```objectivec
- (void)ConsoleOutputSb:(CkoStringBuilder *)sb;
```

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

### Js.Eval

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

```objectivec
- (BOOL)Eval:(CkoStringBuilder *)jscript 
    result:(CkoJsonObject *)result;
```

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

Returns YES for success, NO for failure.

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

### Js.SetCkPermission

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

```objectivec
- (BOOL)SetCkPermission:(NSString *)chilkatClassName 
    permission:(NSString *)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 YES for success, NO for failure.

## Events and callbacks

To receive events, define your own class that inherits from CkoBaseProgress and override just the methods you want to handle. The base class provides an empty implementation of every method, so anything you don't override is simply ignored.

Then create an instance of your class and pass it to the object's setEventCallbackObject: method. From that point on, the object calls your methods as the work proceeds.

**For example:**

```objectivec
  CkoJs *js = [[CkoJs alloc] init];

  MyJsProgress *callbackObj = [[MyJsProgress alloc] init];

  [js setEventCallbackObject:callbackObj];
```

**MyJsProgress interface example:**

```objectivec
#import "CkoBaseProgress.h"

@interface MyJsProgress : CkoBaseProgress {

}

    - (id)init;
    - (void)dealloc;
    - (void)dispose;

    - (void)AbortCheck:(BOOL *)abort;
    - (void)PercentDone:(NSNumber *)pctDone 
        abort:(BOOL *)abort;
    - (void)ProgressInfo:(NSString *)name 
        value:(NSString *)value;
    - (void)TaskCompleted:(CkoTask *)task;
@end
```

### Js.TaskCompleted (event)

`Chilkat 11.7.0 · objc · Js · TaskCompleted · event`

```objectivec
- (void)TaskCompleted:(CkoTask *)task;
```

Called from the background thread when an asynchronous task completes.

## 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.

```objectivec
- (CkoTask *)CallFunctionAsync:(CkoJsonObject *)func 
    result:(CkoJsonObject *)result;
- (CkoTask *)EvalAsync:(CkoStringBuilder *)jscript 
    result:(CkoJsonObject *)result;
```

## Related classes

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