The difference between Callback.call () and callback () in JS

The difference between Callback.call () and callback () in JS
What is the difference between Callback.call () and callback () in JS, for example:
function A () {
Alert (' hello! ');
}
Function B (callback) {
Callback ();
}
Function C (callback) {
Callback.call ();
}
function Test () {
b (a);
C (a);
}
In the test function, the effects of B and C are the same, and the callback function A is executed. What is the difference between these two usages?

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Callback is a callback function. Functions have call and apply methods. The binding context can be dynamic when the function executes.
Because you are here Callback.call () did not pass in any parameters. So Callback.call () is equivalent to callback (). It's not any different.
The context of a function primarily affects the This object in the function.
Under normal circumstances this object is automatically specified according to the run context.
However, the context can be set manually using the call method or the Apply method. The equivalent can be arbitrarily adjusted to whom the this object in the function points.

The difference between Callback.call () and callback () in JS