//输入参数 base 为一种 $.widget对象
//prototype为其它对象
$.widget = function( name, base, prototype ) {
	var namespace = name.split( "." )[ 0 ],
		fullName;
	name = name.split( "." )[ 1 ];
	fullName = namespace + "-" + name;

	if ( !prototype ) {
		prototype = base;
		base = $.Widget;
	}

	// create selector for plugin
	$.expr[ ":" ][ fullName ] = function( elem ) {
		return !!$.data( elem, name );
	};

	$[ namespace ] = $[ namespace ] || {};
	$[ namespace ][ name ] = function( options, element ) {
		// allow instantiation without initializing for simple inheritance
		if ( arguments.length ) {
			this._createWidget( options, element );
		}
	};

	var basePrototype = new base();

        //这是 $.ui.name 比如 $.ui.draggable的初始化代码，它将被绑定到每个DOM元素去
        $[ namespace ][ name ] = function( options, element ) {
		// allow instantiation without initializing for simple inheritance
		if ( arguments.length ) {
			this._createWidget( options, element );  //这是个关键的函数~
                                                                 //options 会被 extend 到 $.namespace.name对象中去
		}
	};

	var basePrototype = new base();
	// we need to make the options hash a property directly on the new instance
	// otherwise we'll modify the options hash on the prototype that we're
	// inheriting from
//	$.each( basePrototype, function( key, val ) {
//		if ( $.isPlainObject(val) ) {
//			basePrototype[ key ] = $.extend( {}, val );
//		}
//	});
	basePrototype.options = $.extend( true, {}, basePrototype.options );
	$[ namespace ][ name ].prototype = $.extend( true, basePrototype, {
		namespace: namespace,
		widgetName: name,
		widgetEventPrefix: $[ namespace ][ name ].prototype.widgetEventPrefix || name,
		widgetBaseClass: fullName
	}, prototype );

	$.widget.bridge( name, $[ namespace ][ name ] ); 

$.widget.bridge = function( name, object ) {      //object是 $.ui.name 静态函数，这个object将被绑定到每个调用$(selector).name()的jqeury DOM对象中
	$.fn[ name ] = function( options ) {                                    //这里定义了ui plugin，比如 $.fn.draggable，是使用UI的入口
		var isMethodCall = typeof options === "string",                 //如果参数为字符串，确定是函数调用
			args = Array.prototype.slice.call( arguments, 1 ),
			returnValue = this;

		// allow multiple hashes to be passed on init
		options = !isMethodCall && args.length ?
			$.extend.apply( null, [ true, options ].concat(args) ) :
			options;

		// prevent calls to internal methods
		if ( isMethodCall && options.charAt( 0 ) === "_" ) {  //确保不调用内部函数，JS语言没有C++的private访问控制啊~
			return returnValue;
		}

		if ( isMethodCall ) {
			this.each(function() {
				var instance = $.data( this, name ),             //取出依附在DOM中的object
					methodValue = instance && $.isFunction( instance[options] ) ?
						instance[ options ].apply( instance, args ) :
						instance;
				// TODO: add this back in 1.9 and use $.error() (see #5972)
				if ( methodValue !== instance && methodValue !== undefined ) {
					returnValue = methodValue;
					return false;
				}
			});
		} else {
			this.each(function() {
				var instance = $.data( this, name );
				if ( instance ) {
					instance.option( options || {} )._init();
				} else {
					$.data( this, name, new object( options, this ) );  
                                        //依附一个对象给这个DOM元素，供以后使用
                                        //这个对象就是 $.namespace.name(option, this)调用 _createWidget生成的，其prototype为
				}
			});
		}

		return returnValue;
	};
};