javascript

There are two ways to define a function in JavaScript and to assign a function variable


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//= = = = = = = = = = = = = = = = = = js function in the two types of definition and function of variable assignment = = = = = = = = = = = = = = = =
//Defining a function in javascript can be interpreted as defining a variable
//Variables in js are weakly typed.
//----------1
//function add1(){
//alert("add1");
//}
//So the function as a variable, as an argument, is add1, which points to the first address that the block stores in memory
var add1=new Function("alert('add1');");//--------2
//The above 1,2 notation is completely equivalent, which is the two ways of declaring functions in js
//In fact, it's add1 that points to the first address of this block of code stored in memory.
//As for how to store, heap or stack, I won't do much research here.

var addtt=add1;//Function names can be assigned or passed as variables
//Addtt points to the body of the function
addtt();
//= = = = = = = = = = = = = = = = = = js function in the two types of definition and function of variable assignment = = = = = = = = = = = = = = = =
//= = = = = = = = = = = = = = = = = = the function variables passed as a parameter = = = = = = = = = = = = = = = = = = = = = = = = = = =
//Basic format:
function add2(fun){
//Pass the function name as an argument
fun();
}
add2(add1);

//--------------------------------------
//This is demonstrated by using a function as an argument and accepting arguments at the same time
function add(a){
return n+10;
}
//A: Numbers. Fun: functions
function addTest(a,fun){
var t=fun(a);
return t;
}
var tt=addTest(22,add);//That's also ok
alert(tt);
//= = = = = = = = = = = = = = = = = = the function variables passed as a parameter = = = = = = = = = = = = = = = = = = = = = = = = = = =
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