How to use a variable value as a property of an object?

Question

Possible Duplicate:
How to create an object property from a variable value in JavaScript?

I want to create an object using a value in a variable as the property name.

I have a variable called propertyName:

propertyName = "first";

How do I use the value stored in this variable as object property, as in the following?

obj.first = something; // 'first' should be extracted from propertyName

Answer 1

Use square bracket notation:

obj[propertyName] = something;

Answer 2

This should work:

object[ propertyName ];

It's an alternative form to the dot notation. What sets it apart from it is that it allows you to dynamically generate the property name using strings.