The topics are:

Objects are values which do not contain any predefined properties or methods (except the toString method), but where new ones can be added. A new, empty object can be created using the Object constructor. For example, the following program creates a new object, stores it in the variable myCar, and adds the properties "name" and "year" to it:

Now:

Since a method is really a property which contains a function value, defining a method simply consists in defining a regular function, then assigning it to a property.

For example, the following program adds a method "start" to the myCar object defined in Rogue Wave Script Objects:

Now, the expression myCar.start() will call the function defined as start_engine. Note that the only reason for using a different name for the function and for the method is to avoid confusion; we could have written:

Inside methods, the this keyword can be used to reference the calling object. For example, the following program defines a method getName, which returns the value of the name property of the calling object, and adds this method to myCar:

Inside constructors, this references the object created by the constructor. When used in a non-method context, this returns a reference on the global object. The global object contains variables declared at toplevel, and built-in functions and constructors.

Objects are created using the following constructor:

In addition to the Object constructor, any user-defined function can be used as an object constructor, using the following syntax:

Inside the constructor, the keyword this can be used to make reference to the object being initialized.

For example, the following program defines a constructor for cars:

Now, calling

creates a new object with the properties name and year, and a start method.

The only object built-in method is: