Use of function functions

The composition of the function

function+ function name (parameter 1, parameter 2) {

function implementation;

}

The function name cannot be the beginning of a number, it can be a letter and an underscore;

function invocation: function name ();

Scope

Variables defined outside the function, called global variables, can be accessed throughout the document.

Variables defined inside a function are local variables and can only be accessed inside the function.

var a=10;

function aa () {

var a=20;

alert (a);

}

alert (a);

AA ()

A function is a data type that can be assigned to a variable

var f=function (b) {

return (B=B+1);

};

Alert (f (5));

Use f (parameter) when invoking

function can access functions inside itself

Function B () {

var a=5;

function bb () {

alert (a);

}

BB ();

}

b ();

Call function to use the return+ function when the intrinsic function has a return value

Function C () {

var a=10;

function bb () {

return a*2;

}

return BB ();

}

Alert (c ())

A function's call to its own intrinsic function

Function d (A, b) {

function DD (a) {

Return a+2

}

Return C=dd (a) +dd (b);

}

Alert (d (2,3))

function calls to other functions

function Add (A, b) {

return a+b;

}

function Sub (A, b) {

return a-B;

}

function bb (x,a,b) {

return x (A, b);

}
Alert (BB (sub,2,3))

Recursion of functions

function cc (a) {

if (a==1) {

return A;

}else{

Return A*CC (--A);

}

}

Alert (CC (4));

Use of function functions