JavaScript Learning Lesson Five this, call, apply

The This object is bound to a function-based execution environment in the run, in the global function, this equals window, and when the function is called as a method of an object, this is equal to that object

This means that the This keyword refers to the caller.

Call, apply example:

1. Simple usage: Bind some functions for passing parameters, calling

2. Used to extend the scope used for function run:

JS does not have a block-level scope concept:

Example of a feature that emulates a block-level scope for a high-level language:

By using the anonymous function self-executing implementation:

Closures:

Closures Example:

JavaScript Learning Lesson Five this, call, apply