[RESOLVED] Difference between object['element'] and object.element?

[pilau]

Hi all, long time no see! How are you doing?

Anyway, here's my question: Is there any difference between object['element'] and object.element?

Thanks a dozen!

[gil davis]

They reference the same element, so the only difference is symantics.

You can use a string, a var containing a string, or an integer within the braces to access an element.

However, the other syntax is literal, and cannot be a var.

Some may also make the comment that this is the "old" way of referencing things, but it still works.

[pilau]

Thanks for your quick reply
Which of the two is the 'old' way?

[gil davis]

(ROFL) both.

The "new" way would involve DOM methods.

[pilau]

Actually, I am not talking about referencing DOM objects, but about defining arrays and defining custom objects (for object oriented scripts). I know how to use DOM methods for DOM HTML objects.

But what about custom Javascript objects? What would you say - which the two is better?

[rnd me]

But what about custom Javascript objects? What would you say - which the two is better?

that like asking "what's better; a car or a chainsaw?"...

for hand-coded source, ob.prop is quicker and more readable.
for machine-generated code, op["prop"] syntax allows spaces, reserved names like ob['class'], var-refs ( ob[stringVar] ), and expressions (ob['pr'+'op'])

[pilau]

that like asking "what's better; a car or a chainsaw?"...

Well consider this, in this case I didn't really know the difference between the car and the chainsaw...

Another question - if I declare an object using one way can I call it's elements using the other?

Also, is one way prefered for custom arrays defined through the Array class and the other for objects defined through custom classes?

Thanks!

[TinKim]

Javascript Guru Douglas Crockford says, you should prefer the dot-notation. The other notation requires a little more work on the js-engines as there is always a new string to handle with myObject["something"].

So, there is only a need for the myObject["something"]-notation if you are going some dynamic way like something = "somewhere"; myObject[something];

Greetings from Germany,
Kim

--
www.youngvisions.net | www.deutscherfussballblog.de | www.schneider.ws

[rnd me]

["xxx"] is called array syntax, but it works just as well for objects.

i don't think there's any speed penatly for using ["xxx"] vs .xxx, the scriptBdy is aready parsed by the time ['xxx'] or .xxx would be assessed. most benchmarks i've seen fail to report any diff, and when they do, it's less than %1...

there is no short-hand of what goes where; you'll have to develop the judgment to decide that for yourself on a case-by-case basis.

will non-special names and hand-coded routines, i would use .xxx first; it's more readable.

[pilau]

Thanks a lot guys
Now I understand this a lot better - on the whole, there isn't any important difference between the two. I was always using the dot method, anyway