Here's a quick lil' addon for Prototype that I use often.

Prototype.Promise(condition, action, interval)
condition is a string that you want met before an action is run.
action is a function that does the action.
interval is the polling rate for condition in seconds, and defaults to 1

So, for example, you may want function foo to run, but only once bar has been set:

function foo(a,b) {
this.retVal=a+b;
}
var thingy = {
retVal:0
};
Prototype.Promise(
'thingy.retVal=5',
foo.bind(thingy,5,10),
5
);


Then, in some point in the mysterious future, thingy.retVal gets set to 5, at which point, the Promise goes into effect, and thingy.retVal becomes 10.

Where I find this particularly useful is in making sure that a document is loaded before doing something (condition="$$('body').length>=1), as you can see it used for the include functions.

Speaking of which, the following include functions are great for getting scripts and stylesheets into your page. I won't bother with examples, as they're pretty straightforward.

Meanwhile, Prototype.scriptPath will point to wherever in your server's heirarchy Prototype was loaded from. The regex, you'll note allows for names like prototype.compressed.js, prototype.modified.js, 2007-09-28.prototype.js, etc - just in case you want to keep track of your various hacks of Prototype, as I do.

This snippet also you to limit the input in a form field to a specified number of characters. It displays a counter so users can see how many characters they have left, and once they reach the limit the field just trims the length to your limit.

The following is a snippet from what I used when I implemented a tagboard to my site. Further revisions could/should read the LIMIT from the maxlength attribute

Returns the keycode of the key we wrote on a textarea/input. works on IE and Firefox

it give us the position of the mouse. works on IE and Firefox

use:
onclick="posicion_mouse(event)"

A wrapper on top of createElement for getting around IE problems with manipulating the name attribute. Unlike most solutions for this, it tests for which method to use once when the page loads rather than every time an element is created. By Chaos of Lost Souls MUD (a text-based fantasy RPG).

Return object by type. Revision 2.

Simple set of functions for capturing and manipulating the className member of an HTMLElement

This is the final version of my Javascript serializer targetted at PHP.

The point:

Objects are most easily passed over the network as serialized strings. Between serialization and unserialization, serialization is by far the easier of the two. Since object passing can sometimes be a process-hungry thing, we want to do things as quickly as possible.

My solution is to always do the hard part in compiled code, while doing the easy part in script. That is, whichever way you're passing an Object, you want to pass it in a natively decoded format for the target.

Since I work mostly in PHP, this meant writing a module that would be able to generate a string that can be decoded with PHP's unserialize() function into a PHP Associative Array (or other applicable type).

Notes:

This lib REQUIRES the Prototype lib. You can hack prototype out of it, of course (by replacing the references to Object.extend() with explicit assignments), but I can't imagine why you'd want to bother; it's used mostly with Ajax.Request anyway.

Previous versions of this code would add the .toPHP() member to the Object prototype. After trying to enumerate things, I found that this is a REALLY bad thing to do, as toPHP springs up where it's not wanted in ALL objects. As a result, I've opted to go the Prototype route and apply it as a member of the Object object.

Please note that if you pass a serialized string to PHP via GET or POST, you'll need to stripslashes() before unserialization.

Javascript sample of use:

var myObject = {
name:'value',
test:['Array','of','strings'],
bool:false,
timestamp: new Date(),
float: 3.1415926539,
number: 42,
func: function () {
alert('Member functions are always omitted from serialization');
}
}
alert(Object.toPHP(myObject));

Output:

a:7:{s:4:"name";s:5:"value";s:4:"test";a:3:{i:0;s:5:"Array";i:1;s:2:"of";i:2;s:7:"strings";}s:4:"bool";b:0;s:9:"timestamp";i:1190897619824;s:5:"float";d:3.1415926539;s:6:"number";i:42;s:4:"func";null}

Sample of subsequent unserialization in PHP (passed via POST as 'myobject')

$myObject=unserialize(stripslashes($_POST['myobject']));
var_dump($myObject);

Output:

array(7) {
["name"]=>
string(5) "value"
["test"]=>
array(3) {
[0]=>
string(5) "Array"
[1]=>
string(2) "of"
[2]=>
string(7) "strings"
}
["bool"]=>
bool(false)
["timestamp"]=>
int(1192296601)
["float"]=>
float(3.1415926539)
["number"]=>
int(42)
["func"]=>
NULL
}

Ok, so I was getting frustrated with the inability to hide data in javascript, as well as a number of other concerns with existing class structures (the requirement to use this.constructor in lieu of self, for example).

As a result, I've thrown together a nice little class constructor that accepts a class definition, as well as a class extender that allows you to build a new class from an existing one, with full access to all that private stuff.

This is a simple fade in / fade out javascript slideshow, search engine friendly with low resource usage.

More info here.

Cheers