objectName.propertyName
Like all JavaScript variables, both the object name (which could be a normal variable) and property name are case sensitive. You can define a property by assigning it a value. For example, let's create an object named myCar and give it properties named make, model, and year as follows:
var myCar = new Object();
myCar.make = "Ford";
myCar.model = "Mustang";
myCar.year = 1969;
Properties of JavaScript objects can also be accessed or set using a bracket notation. Objects are sometimes called associative arrays, since each property is associated with a string value that can be used to access it. So, for example, you could access the properties of the myCar object as follows:
myCar["make"] = "Ford";
myCar["model"] = "Mustang";
myCar["year"] = 1969;
An object property name can be any valid JavaScript string, or anything that can be converted to a string, including the empty string. However, any property name that is not a valid JavaScript identifier (for example, a property name that has space or dash, or starts with a number) can only be accessed using the square bracket notation. This notation is also very useful when property names are to be dynamically determined (when the property name is not determined until runtime). Examples are as follows:
var myObj = new Object(),
str = "myString",
rand = Math.random(),
obj = new Object();
myObj.type = "Dot syntax";
myObj["date created"] = "String with space";
myObj[str] = "String value";
myObj[rand] = "Random Number";
myObj[obj] = "Object";
myObj[""] = "Even an empty string";
console.log(myObj);
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