JavaScript class attributes access to the details of the basic knowledge

How JavaScript class properties are accessed

Copy Code code as follows:

var fish = {
Head:1,
Tail:1,
Feature: {
Speak:false,
Swim:true
}
}

First, the dot operator:

Copy Code code as follows:

Console.log (fish.head);//1
Console.log (fish.tail);//1
Console.log (fish.feature);//object {head:1, tail:1, Feature:object}

Secondly, [] operator:

Copy Code code as follows:

Console.log (fish[' head ');//1

The point to note at this point is that the property name must be a string form
Such as:

Copy Code code as follows:

Console.log (Fish[head]);//Wrong!

So, is the following code correct?

Copy Code code as follows:

For (var prop in fish) {
Console.log (Fish[prop]);
}

The answer is yes, because traversing object properties is a string type, that is, prop in turn, ' head ', ' tail ', ' feature '.