About JavaScript Interop

Ultralight is built on JavaScriptCore-- the same high-performance JavaScript engine used by Safari/WebKit on macOS and iOS.

We expose low-level C bindings to JavaScriptCore so that you can seamlessly integrate your native code with JavaScript running on a page.

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C++ Wrapper for JavaScriptCore
We offer a wrapper to simplify usage from C++. See JSHelpers.h in the AppCore API

Using the JavaScriptCore API

To use the JavaScriptCore API in your code, just include <JavaScriptCore/JavaScript.h>:

#include <JavaScriptCore/JavaScript.h>

You can browse the API headers for JavaScriptCore by clicking here.

API Type	Description
JSContextRef	A JavaScript execution context, you will need this to make most calls in JavaScriptCore.
JSValueRef	The base type for all JavaScript values (eg, `Number`, `String`, `Object`, `Boolean`, etc.). This is a garbage-collected type.
JSObjectRef	A JavaScript object-- this value is technically typedef'd to the same underlying type as `JSValueRef` and can be passed anywhere that accepts a `JSValueRef`. This is a garbage-collected type.
JSStringRef	A raw UTF-16 string buffer for passing strings to/from JavaScript.
JSClassDefinition	Used to create custom JavaScript objects that wrap native objects.