function parameters
Formal parameters :
the parameters in parentheses at the time of definition : the parameters in parentheses at the time of calling
function add(a,b){
var num=a+b;
return num;
}
var x=add(1,2); //3
var y=add(1,2,3); //实参>形参 3
var z=add(1); //实参<形参 NaN
arguments group of actual parameters
The arguments are not an array, but an array-like concept (with array characteristics, but not with array methods)
function add(a,b){
console.log(a); //a
console.log(b); //b
console.log(argument[2]); //c
}
add(a,b,c);
| array base slot method | Index attribute length | |
|---|---|---|
| array | have | have |
| arguments | none | have |