Basic description of JavaScript Functions and javascript Functions

Basic description of JavaScript Functions and javascript Functions

What is a function?

A function is a code segment that completes a function.

A function is a code segment that can be executed repeatedly.

Convenient function Management and Maintenance

Custom Functions

Use the function keyword

Function Name ([parameter,...]) {

Code segment;

Return value ;}

Note:

The function name must not contain special characters.

The function name should have a clear meaning

It is recommended that the function name follow the hump mark or underline method.

Function names are case sensitive

If the function name is repeated, overwriting is generated.

A function can have either a parameter or no parameter. Either a parameter or multiple parameters can exist.

The function adds the return value through return. If no return is returned, undefined is returned by default.

No function call or execution

Anonymous Functions

Function expressions can be stored in variables or used as a function.

Anonymous functions can be passed as parameters to other functions, and the receiver functions can complete some functions through the passed functions.

You can use anonymous functions to execute some one-time tasks.

Construct a Function through Function ()

Defined by built-in JavaScript Function Constructor (Function ()

var myFunction=new Function('a','b','return a+b');var myFunction=function(a,b){return a+b;};

Note:

The above two methods are equivalent.

Avoid using the new keyword whenever possible

Source code

<! DOCTYPE html> 
Running result:

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