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adding arguments

function createCar() {

var oTempCar = new Object;

oTempCar.color = “red”;

oTempCar.doors = 4;

oTempCar.mpg = 23;

oTempCar.showColor = function () {

alert(this.color)

};

return oTempCar;

}

var oCar1 = createCar();

var oCar2 = createCar();

Here, all the previous lines of code are contained within the

createCar()

function, including one extra

line, which returns the car (

oTempCar

) as the function value. When this function is called, it creates a

new

Object

and assigns all the properties necessary to replicate the car object described earlier. Using

this method, it is easy to create two (or more) versions of a car object (

oCar1

and

oCar2

) that have the

exact same properties. Of course, the

createCar()

function can also be modified to allow the passing in

of default values for the various properties instead of just assigning default values:

function createCar(sColor, iDoors, iMpg) {

var oTempCar = new Object;

oTempCar.color = sColor;

oTempCar.doors = iDoors;

oTempCar.mpg = iMpg;

oTempCar.showColor = function () {

alert(this.color)

};

return oTempCar;

}

var oCar1 = createCar(“red”, 4, 23);

var oCar1 = createCar(“blue”, 3, 25);

oCar1.showColor(); //outputs “red”

oCar2.showColor(); //outputs “blue”

By adding arguments to the

createCar()

function, it is possible to assign values to the color, doors,

and mpg properties of the car object being created. This leaves two objects with the same properties but

different values for those properties.

As ECMAScript became more formalized, however, this method of creating objects fell out of favor and

is typically frowned upon today. Part of the reason for this was semantic (it doesn’t look as appropriate

as using the

new

operator with a constructor), and part was functional. The functional problem has to do

with the creation of object methods using this paradigm. In the previous example, every time the

createCar()

function is called, a new function is created called

showColor()

, meaning that every

object has its own version of

showColor()

when, in reality, each object should share the same function.

Object Basics

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