The understanding of this JS

Points for one or four different modes of minor

1. When the function calls the mode, this points to the window

2. When the method invokes the pattern, this points to the object where the method is located

3. In the constructor mode, this points to the newly generated instance

When 4.apply/call invokes a pattern, this points to the first parameter in the Apply/call method

The most used should be 2 and 3, in JS Object-based programming, these two should be the most common

Ii. Apply and call

1. Use of apply and call

All functions contain both methods, and you can assume that the apply and call methods force the this within a function to point to an object.

2. Difference between apply and call

The difference between apply and call is only the this reference within the called function (method), which refers to the object being passed as the first parameter of the Apply/call. and the difference between apply and call is how they are passed on to other parameters.

The understanding of this JS