A cleaner approach to jquery plugins. Separate the code for the plugin's functionality from the assignment into the jQuery namespace. Taken from various articles/presos by Alex Sexton and Paul Irish, and #jquery IRC chats. With enthusiasm for Object.creat

jquery.demo-plugin.js

(function( $ ){
   
   /* 
    A cleaner approach to jquery plugins. Separate the code for the plugin's functionality from 
    the assignment into the jQuery namespace.  
    
    Taken from various articles/presos by Alex Sexton and Paul Irish, and #jquery IRC chats.
    With enthusiasm for Object.create() toned down after http://news.ycombinator.com/item?id=2594521
    */

   /* 
    Approach 1
    
    Most common. Not so easy on the eyes.
    
    Nested anonymous functions and loops galore
    
    */

   $.fn.fader = function ( options ) {
     var opts = $.extend({}, $.fn.pluginname.defaults, options);                 
     if( this.length ) {    
       return this.each(function(){
         if( $(this).find('li').length ){
           $(this).find('li').each(function(){
             /* ... more stuff ... */
           });      
         }
       });
     }
   };

   /* 
    Approach 2
    
    Detach plugin functionality from plugin definition.
    Better, model the plugin's functionality as a **class** 
    ( object, whatevs ). Init one new object for each element
    your plugin is acting on. 
    
    */

   var Fader = function ( el ){
     // ... do some validation
     this.$el = el;
     this.init();
   };

   Fader.prototype = {
     init: function (){},
     otherMethod: function (){}
   };

   $.fn.fader = function () {
     if( !this.length ){ return this; }
     return this.each(function(){
        new Fader( $(this) ); 
     });  
   };

   /*
    Approach 2a
    
    Depending on your feelings about Object.create() 
    vs new F(), define an object literal with methods. 
    Pass it to Object.create() when iterating 
    over set of elements.
    
    */

   var Fader2 = {
     init: function (){},
     otherMethod: function (){}
   };

   /* with Object.create */
   $.fn.fader2 = function () {
     if( !this.length ){ return this; }
     return this.each(function(){
       var myFader = Object.create( Fader );
       myFader.init( $(this) );                 
     });  
   };


   /*
    Approach 3
     
    Uses options. Completely detach
    the plugin definition from the assignment
    into the jQuery plugin namespace
     
    */

   var Fader = function ( el, options ){
     // validate
     this.$el = el;
     $.extend( this.options, options );
     this.init();
   };

   Fader.prototype = {
     init: function (){},
     options: {
       duration: 1000,
       fadeToOpacity: .3
     }
   };

   var faderPlugin = function ( options ) {
     if( !this.length ){ return this; }
     return this.each(function(){                     
       if( options ) {            
         var myFader = new Fader( $(this), options ); 
       } else {         
         var myFader = new Fader( $(this) ); 
       }
       // Save the instance of the object in the element's data store
       $(this).data('fader', myFader );
     });   
   };

   $.fn.fader = faderPlugin;
 
 })(jQuery);

jquery.placeholdertext.js

(function($){

   /**
    * @class Binds a text value to focus and blur events. Commonly 
    * used for UI elements like search boxes, text input fields. Useful
    * for adding place holder text in browsers that don't support HTML5 
    * 'placeholder' attribtute.
    * 
    * @constructor 
    * Configure your instances 
    */
   var PlaceholderText = function ( elem, options ) {
     if ( !elem ){ return false; }
     if ( !options ){ return false; }

     /* slim constructor that mostly  
        calls other methods 
      */
     
     // bunch of validations 
     if ( this.before( elem ) && this.configure( options ) ){
       this.attachEvents();
     }
   };
   
   PlaceholderText.prototype = {
     options: {},
     before: function ( elem ) {
       if( elem.jquery  /* is jquery object? */ ){
         this.$elem = elem;
         return true;
       } else if( elem.tagName /* is dom element? */ ) {
         // make it a jquery object
         this.$elem = $(elem);
         return true;
       } else {
         return false;
       }                     
     },
     configure: function ( options ) {
       /* only proceed if it's an 
        * input tag or text area 
        * */
       if ( this.$elem.is('input') || this.$elem.is('textarea')  ){       
         $.extend( this.options, options );
         return true;
       } else {
         return false;
       }             
     },
     attachEvents: function () {
       this.$elem.bind('blur', $.proxy(this.blurHandler, this) );
       this.$elem.bind('focus', $.proxy(this.focusHandler, this) );
     },
     blurHandler: function ( e ) {
       if( this.$elem.val() === ''  ){
         this.$elem.val( this.options.text );
       }               
     },
     focusHandler: function ( e ){
       if( this.$elem.val() === this.options.text ){
         this.$elem.val('');
       }
     }
   };

   /* Code that instantiates your 'class' (object), defined above,
    * once for each element in jQuery wrapped set
    */
   var placeHolderTextPlugin = function ( options ) {
     if( !this.length ) { return this; }
     return this.each(function () {
       var placeHolder = new PlaceholderText( $(this), options );
       $(this).data('placeHolderText', placeHolder );                 
     });
   };

   // attach plugin
   $.fn.placeHolderText = placeHolderTextPlugin;   
   

   // call it like
   $(function () {
       $('input').placeHolderText({ text: 'Search' });
     });

 })(jQuery);