jQuery.extend(object);

$.extend({ 
　　addMethod : function(a, b){return a + b;}  // $.addMethod(1, 2); //return 3
});

jQuery.fn.extend(object);
jQuery.fn = jQuery.prototype

$.fn.extend({ 
  getInputText:function(){ 
    $(this).click(function(){ 
      alert($(this).val()); 
    }); 
  } 
});

$("#username").getInputText();

(function($){ 
  $.fn.yourPluginName = function(options){ 
    //各种属性和参数 

    var options = $.extend(defaults, options); 

    this.each(function(){ 
      //插件的实现代码

    }); 
  }; 
})(jQuery);

$.extend(defaults, options);

jQuery.fn.myPlugin = function() {

 // Do your awesome plugin stuff here

};

(function( $ ) {
 $.fn.myPlugin = function() {

  // Do your awesome plugin stuff here

 };
})( jQuery );

(function( $ ){

 $.fn.myPlugin = function() {

  // there's no need to do $(this) because
  // "this" is already a jquery object

  // $(this) would be the same as $($('#element'));

  this.fadeIn('normal', function(){

   // the this keyword is a DOM element

  });

 };
})( jQuery );
$('#element').myPlugin();

(function( $ ){

 $.fn.maxHeight = function() {

  var max = 0;

  this.each(function() {
   max = Math.max( max, $(this).height() );
  });

  return max;
 };
})( jQuery );
var tallest = $('div').maxHeight(); // Returns the height of the tallest div

(function( $ ){

 $.fn.lockDimensions = function( type ) { 

  return this.each(function() {

   var $this = $(this);

   if ( !type || type == 'width' ) {
    $this.width( $this.width() );
   }

   if ( !type || type == 'height' ) {
    $this.height( $this.height() );
   }

  });

 };
})( jQuery );
$('div').lockDimensions('width').css('color', 'red');

(function( $ ){

 $.fn.tooltip = function( options ) { 

  // Create some defaults, extending them with any options that were provided
  var settings = $.extend( {
   'location'     : 'top',
   'background-color' : 'blue'
  }, options);

  return this.each(function() {    

   // Tooltip plugin code here

  });

 };
})( jQuery );
$('div').tooltip({
 'location' : 'left'
});

(function( $ ){

 $.fn.tooltip = function( options ) { 
  // THIS
 };
 $.fn.tooltipShow = function( ) {
  // IS
 };
 $.fn.tooltipHide = function( ) { 
  // BAD
 };
 $.fn.tooltipUpdate = function( content ) { 
  // !!! 
 };

})( jQuery );

(function( $ ){

 var methods = {
  init : function( options ) { 
   // THIS 
  },
  show : function( ) {
   // IS
  },
  hide : function( ) { 
   // GOOD
  },
  update : function( content ) { 
   // !!! 
  }
 };

 $.fn.tooltip = function( method ) {

  // Method calling logic
  if ( methods[method] ) {
   return methods[ method ].apply( this, Array.prototype.slice.call( arguments, 1 ));
  } else if ( typeof method === 'object' || ! method ) {
   return methods.init.apply( this, arguments );
  } else {
   $.error( 'Method ' + method + ' does not exist on jQuery.tooltip' );
  }  

 };

})( jQuery );

// calls the init method
$('div').tooltip(); 

// calls the init method
$('div').tooltip({
 foo : 'bar'
});
// calls the hide method
$('div').tooltip('hide'); 
// calls the update method
$('div').tooltip('update', 'This is the new tooltip content!');

(function( $ ){

 var methods = {
   init : function( options ) {

    return this.each(function(){
     $(window).bind('resize.tooltip', methods.reposition);
    });

   },
   destroy : function( ) {

    return this.each(function(){
     $(window).unbind('.tooltip');
    })

   },
   reposition : function( ) { 
    // ... 
   },
   show : function( ) { 
    // ... 
   },
   hide : function( ) {
    // ... 
   },
   update : function( content ) { 
    // ...
   }
 };

 $.fn.tooltip = function( method ) {

  if ( methods[method] ) {
   return methods[method].apply( this, Array.prototype.slice.call( arguments, 1 ));
  } else if ( typeof method === 'object' || ! method ) {
   return methods.init.apply( this, arguments );
  } else {
   $.error( 'Method ' + method + ' does not exist on jQuery.tooltip' );
  }  

 };

})( jQuery );
$('#fun').tooltip();
// Some time later...
$('#fun').tooltip('destroy');

(function( $ ){

 var methods = {
   init : function( options ) {

    return this.each(function(){

     var $this = $(this),
       data = $this.data('tooltip'),
       tooltip = $('<div />', {
        text : $this.attr('title')
       });

     // If the plugin hasn't been initialized yet
     if ( ! data ) {

      /*
 Do more setup stuff here
 */

      $(this).data('tooltip', {
        target : $this,
        tooltip : tooltip
      });

     }
    });
   },
   destroy : function( ) {

    return this.each(function(){

     var $this = $(this),
       data = $this.data('tooltip');

     // Namespacing FTW
     $(window).unbind('.tooltip');
     data.tooltip.remove();
     $this.removeData('tooltip');

    })

   },
   reposition : function( ) { // ... },
   show : function( ) { // ... },
   hide : function( ) { // ... },
   update : function( content ) { // ...}
 };

 $.fn.tooltip = function( method ) {

  if ( methods[method] ) {
   return methods[method].apply( this, Array.prototype.slice.call( arguments, 1 ));
  } else if ( typeof method === 'object' || ! method ) {
   return methods.init.apply( this, arguments );
  } else {
   $.error( 'Method ' + method + ' does not exist on jQuery.tooltip' );
  }  

 };

})( jQuery );