Two common methods for defining classes in JavaScript

1. Hybrid constructor/prototype

function Car(sColor, iDoors, iMpg) { this .color = sColor;this .doors = iDoors;this .mpg = iMpg;this .drivers = new Array(“Mike”, “Sue”);}Car.prototype.showColor = function () {alert( this .color);};var oCar1 = new Car(“red”, 4 , 23 );var oCar2 = new Car(“blue”, 3 , 25 );oCar1.drivers.push(“Matt”);alert(oCar1.drivers); // outputs “Mike,Sue,Matt”alert(oCar2.drivers); // outputs “Mike,Sue”

Advantage: it has the advantages of other methods, but has no disadvantages of other methods.

Deficiency: lack of encapsulation

2. Dynamic Prototype

function Car(sColor, iDoors, iMpg) { this .color = sColor;this .doors = iDoors;this .mpg = iMpg;this .drivers = new Array(“Mike”, “Sue”);if ( typeof Car._initialized == “undefined”) {Car.prototype.showColor = function () {alert( this .color);} ;Car._initialized = true ;}}

Advantage: encapsulation is better than the previous method

In short, the above two methods are currently the most widely used. Try to use them to avoid unnecessary problems.