Global execution context

As explained in Secrets of the JavaScript Ninja, Second Edition

The global execution context and its associated object value, which can serve as this in non-strict function calls without an explicit receiver.

JavaScript creates one global execution context when a program starts. It differs from a function execution context, which is created each time a function is invoked. The engine uses execution contexts to track code execution; a call stack keeps track of the active context and those waiting to resume. section 5.3

Figure 5.6. The behavior of the execution context stack

See how the execution context stack tracks function calls and returns. section 5.3

How Secrets of the JavaScript Ninja, Second Edition covers it

How deep it goes

Defines global and function execution contexts and their role in the call stack, without detailing their internal structure.

Examples

Shows repeated calls to skulk, which invokes report, to illustrate function execution contexts.

What you can do after

Understand how execution contexts track function calls and returns.

How it connects

Connects the global execution context to function execution contexts, the call stack, and single-threaded execution.

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Related concepts

• windowequivalent to · The browser window object is the global object for a browsing context, exposing its document, JavaScript environment, and associated browser APIs.
• execution contextkind of · An internal JavaScript runtime record that tracks the code being evaluated and the environment used to resolve identifiers.
• execution contextkind of · An execution context is the runtime environment and associated state that govern how a computation executes, including its bindings, resources, or scheduling.
• function bindingused by · Function binding is the creation of a function with a predetermined this value and, optionally, preset arguments.
• contextkind of · Context is the surrounding information, state, or circumstances that condition how an entity, event, or task is interpreted or how a system behaves.
• function execution contextcontrasts with · An execution context created for evaluating a particular function invocation in JavaScript.

This explainer was generated by Manning's knowledge graph from the text of Secrets of the JavaScript Ninja, Second Edition. The section links point to the parts of the book it draws on.