General questions 1

[Geee]

Hi, anyone who has read my posts will know I'm new to the whole JS scene and I just had a couple of questions...

I've been learning by following tutorials and dissecting others code. I noticed straight away that variable names have no prefix like they do in other languages, but when coding I have automatically slipped a $ into the variable name and it still works. Does this matter, or does the $ cast the variable as a certain type, like string or something?

Is it possible to refer to a variable by a variable? This sound confusing but in PHP I use $$var quite a lot. Is it possible to do anything similar in JS?

Thanks guys.

-Geeeeeeeeeeeeeeeeeeeeeeee-

 

[Diancecht]

AFAIK, the $ thingie just makes nothing appart from making your code harder to read or maintain.

And no, there isn't any kind of pointer in Javascript.

Cheers,
Dian

 

[BillyRayPreachersSon]

Is it possible to refer to a variable by a variable?

Yes.

For example:

var abc = '123;'
alert(abc);  // should show '123';

var someVar = 'abc';
alert(window[someVar]);  // should show '123';

Hope this helps,
Dan

Coedit Limited - Delivering standards compliant, accessible web solutions

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[Geee]

AFAIK, the $ thingie just makes nothing appart from making your code harder to read or maintain.

I don't understand how this is the case to be honest. I find using a prefix on a variable makes the code EASIER to read as I can pick out the fact its a variable due to the $ sign. Care to expand a little?

-Geeeeeeeeeeeeeeeeeeeeeeee-

 

[BillyRayPreachersSon]

I don't understand that rationale, either. It's personal preference.

From the Moz JS 1.5 core guide section on variable names (

http://developer.mozilla.org/en/docs/Core_JavaScript_1.5_Guide:Variables):

A JavaScript identifier must start with a letter, underscore (_), or dollar sign ($); subsequent characters can also be digits (0-9). Because JavaScript is case sensitive, letters include the characters "A" through "Z" (uppercase) and the characters "a" through "z" (lowercase).

Starting with JavaScript 1.5, you can use ISO 8859-1 or Unicode letters such as å and ü in identifiers. You can also use the \uXXXX Unicode escape sequences listed on page Unicode Escape Sequences as characters in identifiers.

Dan

Coedit Limited - Delivering standards compliant, accessible web solutions

[tt]Dan's Page [blue]@[/blue] Code Couch

http://www.codecouch.com/dan/

[/tt]

 

[Geee]

Great, I shall continue using the good old dollar sign then. Thanks for the help Dan.

-Geeeeeeeeeeeeeeeeeeeeeeee-