[jQuery] Best practices: Wait to reference objects? Classes like PHP? How do you stay organized with little overhead?

[jQuery] Best practices: Wait to reference objects? Classes like PHP? How do you stay organized with little overhead?


Hello,
I just have a quick question about jQuery best practices...
I have been wondering for a while now, is it bad practice for me to
make references to objects outside of the block of code they are used
in?
For example, in my master JS file I might have this code:
===================
// Start closure:
$(function() {
    var $parentObj = $('#parentContianer');
    var $childObj1 = $('#childEle1');
    var $childObj2 = $('#childEle2');
    var $childObj3 = $('#childEle3');
    var $childObj4 = $('#childEle4');
    var $childObj5 = $('#childEle5');
    var $childObj6 = $('#childEle6');
    if($parentObj) { // Parent object exists, execute code block:
        ... do something with child objects ....
    }
});
// End closure.
===================
HTML:
===================
<body>
<div id="parentContianer">
    <div id="#childEle1"></div>
    <div id="#childEle2"></div>
    <div id="#childEle3"></div>
    <div id="#childEle4"></div>
    <div id="#childEle5"></div>
    <div id="#childEle6"></div>
</div>
</body>
===================
Should I avoid referencing those child objects only until the parent
object exists?
I really like keeping all of my used variables at the top of my JS (so
I know what vars I am using and such), but I am just not sure how to
best handle object references... I do not want to do unecessary
lookups.
Is there anyway I could do something like a simple PHP class, but with
JS (psuedo js/php code below):
===================
<?php
class Myclass {
    var $parentObj = $('#parentContianer');
    var $childObj1 = ''
    var $childObj2 = ''
    var $childObj3 = ''
    var $childObj4 = ''
    var $childObj5 = ''
    var $childObj6 = ''
    // Class constructor:
    function Myclass() {
        if($this->parentObj) {
            $this->childObj1 = $('#childEle1');
            $this->childObj2 = $('#childEle2');
            $this->childObj3 = $('#childEle3');
            $this->childObj4 = $('#childEle4');
            $this->childObj5 = $('#childEle5');
            $this->childObj6 = $('#childEle6');
            Init(); // Call Init() method.
        } else { return false; } // If parentObj does not exist, quit.
    }
    function Init() {
        $foo1 = $this->childObj1;
        $foo2 = $this->childObj2;
        ... Do more stuff with the child objects here ...
    }
}
?>
===================
Basically, I want to keep my code organized and readable... But I also
want to keep the overhead minimal.
Hehe, am I making sense here?
Any tips/advice/links ya'll could send my way would be super
helpful!!!!
Thanks!
Cheers,
Micky Hulse