Object arrays in JavaScript

Question

If I do this,

var element = {};
alert(element);
element[name] = "stephen";
alert(element.name);

Why doesn't element.name work?

Nick Craver · Accepted Answer · 2010-10-21 18:20:02Z

17

When using bracket notation, (unless it's a variable) it needs to be in qoutes, like this:

var element = {}; 
alert(element); 
element["name"] = "stephen"; 
alert(element.name);

You cant test it out here. To explain what I mean by "unless it's a variable", this would also work:

var myVariable = "name";
element[myVariable] = "stephen";

answered Oct 21, 2010 at 18:20

Nick Craver

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Comments

Adam · Accepted Answer · 2010-10-21 18:20:58Z

8

Because name should be in quotes. This works:

var element = {};
alert(element);
element['name'] = "stephen";
alert(element.name);

answered Oct 21, 2010 at 18:20

Adam

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Peter Mortensen · Accepted Answer · 2011-01-18 17:51:27Z

0

This is the reason why you may want to get an object's property dynamically. For example:

You have a variable, but you can't be sure of its value. The server send you the variable value so you should write like this.

obj[name].age // Here the name is a variable, and it can be changed in every page refresh, for example.

But if you want to set obj['name'] = 'Lorenzo' you have to use quotes.

Think like obj[name] is used for set, obj['name'] is used for get.

Peter Mortensen

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answered Oct 21, 2010 at 19:19

Fatih Acet

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