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jquery javascript

in Getting Started • 12 years ago

I'm new to jquery but have done some js coding in the past. My initial interest is in the jq js code file. I find it a bit intimidating to unravel. I have a 700 page js book that doesn't seem to touch a lot of this. My questions:

1 What is this structure?

(

function( window, undefined ) {..}(window);

I've searched about and I think I understand it is an anonymous function that is automatically run on load, passing in a ref to the current browser window. Any other comments appreciated.

2 $

Where does the $ asignment come from. I can't see any reference to an alias of jquery to $?

3 Labels against functions

pushStack:

function( elems, name, selector ) {..} etc

I see a label before anon functions, then the label name seems to be used as a name for the function. Whats that about, I see no mention in book about this.

4 Commas

Lots of these label/functions are separated by commas, are these global variables or what. Any overview of general structure would be appreciated.

Thanks to anyone who can be bothered to answer these confusions.

Replies(2)

kbwood.au

Re: jquery javascript

12 years ago

1. Yes, it's an anonymous function that is defined and invoked immediately (not on load). It also serves as a closure for anything defined within it, i.e. variables, etc. within it are not visible externally.

2. The $ assignment is done at the very bottom of the jQuery file.

window.jQuery = window.$ = jQuery;

3. and 4. These are related. The labels appear within the context of an object definition and so are naming the following item, in this case a function. Because these are items within an object, they are separated by commas.

jQuery.fn = jQuery.prototype = {
init: function( selector, context ) {
...
},
selector: "",
...
pushStack: function( elems, name, selector ) {
...
},
...
};

dreamdog

Re: jquery javascript

12 years ago

Thanks for the comprehensive reply, all understood.

Actually, after posting this I returned to scratching my head a lot and came to the same conclusions you have outlined,

Javascript is a strange animal to deal with, after C#/C++, I sort of know the rules but find it difficult to be flu

ent with them.

The $ thing is a good example of declaring and using properties on the fly, forgot that one!!

The literal object notation I also forgot, thats why I thought they were labels. I suppose I would recommend that the file has a few more strucrural comments to make it easier for us part-time js progs.

Many thanks again.

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