Conceptual Comprehension and Usage Analysis of JavaScript Tune Function

The instance of this paper tells the conceptual understanding and usage of the JavaScript callback function. Share to everyone for reference, specifically:

JS code will be up to the next line, but sometimes we need Wait until the end of the operation, then the next operation, this time you need to use the callback function.


Because the function is actually an object, it can be stored in the variable, passed to another function through the parameter, in the function Internal creation, returning from the function “, because the function is a built-in object, we can pass it as a parameter to another function, execute it in the function, or even return it, it has been” professional programmer ” It is a difficult technology.

English explanation of the callback function is:

a callback is a function That Is Passed as an argument to another function and is executed after ITS Parent Function HAS Completed.

Translated is: The callback function is a function that is passed to another function as a variable, which is executed after the main function is executed.

Function A has a parameter Function B, Function B will be called executed after the Function A is executed. 3. How to use the callback function

The code is as follows:

 Function A ("This is a Parent function a"); var m = 1; var n = 3; Return CallbackFunction (m, n);} funcTion B (M, N) {Alert ("This is a callback function B"); Return M + N;} $ ("{var result = a (b); Alert (" Result = "+ result);}   

 This is a Parent function a this is a callback function BRESULT = 4   
The function first executes the subject function A, then call the callback function B, and finally return the return value of the function A.

More about JavaScript Related Contents View this Topic: “JavaScript Common Function Skills Summary”, “JavaScript Object-Oriented Getting Started Tutorial”, “JavaScript Error and Debugging Skills Summary”, “JavaScript Data Structure and Algorithm Skills Summary “and” Summary of JavaScript Mathematical Computing “

It is hoped that this article will help you JavaScript programming.

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