Object Objects

To create an object the new expression is used:

var myObj = new Object();

myObj.address = "123 Any Street";
myObj.state = "TX";
myObj.func = myFunc;  // myFunc is the name of some function

You can also write a function as a constructor and then use that to create objects.

function student (name, major, gpa)
{
  this.name = name;
  this.major = major;
  this.gpa = gpa;
}

var someStudent = new student ("Mickey Mouse", "Dance", 3.84);

String Objects

A String object is created by using the String constructor in a new expression and supplying a string as an argument.

var name = new String ("John Doe");

A String object can be coerced to a string value by calling the String constructor as a function. When String is called without the new expression then it acts as a function and performs type conversions. For example:

var ten = String ( 10 );

Returns a string value (not a String object) computed by the toString() method.

Math Objects

The Math object has attribues and provides methods for basic mathematical functions. To call upon an attribute or method use the name of the object Math followed by the dot operator and then the name of the attribute or function - Math.PI or Math.sqrt(). The convention is similar to that in Java where Math is the name of the class and all its methods are static, so that one does not need to create an object to access the methods.

Date Objects

The Date object contains a number indicating a particular instant of time to within one millisecond. Time is measured in milliseconds since 01 January 1970 UTC. Leap seconds are ignored.

There are several constructors of the Date object but in its simplest form a Date object is created using the new operator.

var today = new Date();