read.js

这是一个ajax的例子大家好好的看看就是一个鱼眼的效果

if(!dojo._hasResource["dojo.data.api.Read"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojo.data.api.Read"] = true;
dojo.provide("dojo.data.api.Read");
dojo.require("dojo.data.api.Request");

dojo.declare("dojo.data.api.Read", null, {
	//	summary:
	//		This is an abstract API that data provider implementations conform to.  
	//		This file defines methods signatures and intentionally leaves all the
	//		methods unimplemented.  For more information on the dojo.data APIs, 
	//		please visit: http://www.dojotoolkit.org/node/98

	getValue: function(	/* item */ item, 
						/* attribute-name-string */ attribute, 
						/* value? */ defaultValue){
		//	summary:
		//		Returns a single attribute value.
		//		Returns defaultValue if and only if *item* does not have a value for *attribute*.
		//		Returns null if and only if null was explicitly set as the attribute value.
		//		Returns undefined if and only if the item does not have a value for the
		//		given attribute (which is the same as saying the item does not have the attribute). 
		// description:
		//		Saying that an "item x does not have a value for an attribute y"
		//		is identical to saying that an "item x does not have attribute y". 
		//		It is an oxymoron to say "that attribute is present but has no values" 
		//		or "the item has that attribute but does not have any attribute values".
		//		If store.hasAttribute(item, attribute) returns false, then
		//		store.getValue(item, attribute) will return undefined.
		//
		//	item:
		//		The item to access values on.
		//	attribute:
		//		The attribute to access represented as a string.
		//	defaultValue:
		//		Optional.  A default value to use for the getValue return in the attribute does not exist or has no value.
		//
		//	exceptions:
		//		Throws an exception if *item* is not an item, or *attribute* is not a string
		//	example:
		//	|	var darthVader = store.getValue(lukeSkywalker, "father");
		var attributeValue = null;
		throw new Error('Unimplemented API: dojo.data.api.Read.getValue');
		return attributeValue; // a literal, an item, null, or undefined (never an array)
	},

	getValues: function(/* item */ item,
						/* attribute-name-string */ attribute){
		//	summary:
		// 		This getValues() method works just like the getValue() method, but getValues()
		//		always returns an array rather than a single attribute value.  The array
		//		may be empty, may contain a single attribute value, or may contain
		//		many attribute values.
		//		If the item does not have a value for the given attribute, then getValues()
		//		will return an empty array: [].  (So, if store.hasAttribute(item, attribute)
		//		has a return of false, then store.getValues(item, attribute) will return [].)
		//
		//	item:
		//		The item to access values on.
		//	attribute:
		//		The attribute to access represented as a string.
		//
		//	exceptions:
		//		Throws an exception if *item* is not an item, or *attribute* is not a string
		//	example:
		//	|	var friendsOfLuke = store.getValues(lukeSkywalker, "friends");
		var array = [];
		throw new Error('Unimplemented API: dojo.data.api.Read.getValues');
		return array; // an array that may contain literals and items
	},

	getAttributes: function(/* item */ item){
		//	summary:
		//		Returns an array with all the attributes that this item has.  This
		//		method will always return an array; if the item has no attributes
		//		at all, getAttributes() will return an empty array: [].
		//
		//	item:
		//		The item to access attributes on.
		//
		//	exceptions:
		//		Throws an exception if *item* is not an item, or *attribute* is not a string
		//	example:
		//	|	var array = store.getAttributes(kermit);
		var array = [];
		throw new Error('Unimplemented API: dojo.data.api.Read.getAttributes');
		return array; // array
	},

	hasAttribute: function(	/* item */ item,
							/* attribute-name-string */ attribute){
		//	summary:
		//		Returns true if the given *item* has a value for the given *attribute*.
		//
		//	item:
		//		The item to access attributes on.
		//	attribute:
		//		The attribute to access represented as a string.
		//
		//	exceptions:
		//		Throws an exception if *item* is not an item, or *attribute* is not a string
		//	example:
		//	|	var trueOrFalse = store.hasAttribute(kermit, "color");
		throw new Error('Unimplemented API: dojo.data.api.Read.hasAttribute');
		return false; // boolean
	},

	containsValue: function(/* item */ item,
							/* attribute-name-string */ attribute, 
							/* anything */ value){
		//	summary:
		//		Returns true if the given *value* is one of the values that getValues()
		//		would return.
		//
		//	item:
		//		The item to access values on.
		//	attribute:
		//		The attribute to access represented as a string.
		//	value:
		//		The value to match as a value for the attribute.
		//
		//	exceptions:
		//		Throws an exception if *item* is not an item, or *attribute* is not a string
		//	example:
		//	|	var trueOrFalse = store.containsValue(kermit, "color", "green");
		throw new Error('Unimplemented API: dojo.data.api.Read.containsValue');
		return false; // boolean
	},

	isItem: function(/* anything */ something){
		//	summary:
		//		Returns true if *something* is an item and came from the store instance.  
		//		Returns false if *something* is a literal, an item from another store instance, 
		//		or is any object other than an item.
		//
		//	something:
		//		Can be anything.
		//
		//	example:
		//	|	var yes = store.isItem(store.newItem());
		//	|	var no  = store.isItem("green");
		throw new Error('Unimplemented API: dojo.data.api.Read.isItem');
		return false; // boolean
	},

	isItemLoaded: function(/* anything */ something) {
		//	summary:
		//		Returns false if isItem(something) is false.  Returns false if
		//		if isItem(something) is true but the the item is not yet loaded
		//		in local memory (for example, if the item has not yet been read
		//		from the server).
		//
		//	something:
		//		Can be anything.
		//
		//	example:
		//	|	var yes = store.isItemLoaded(store.newItem());
		//	|	var no  = store.isItemLoaded("green");
		throw new Error('Unimplemented API: dojo.data.api.Read.isItemLoaded');
		return false; // boolean
	},

	loadItem: function(/* object */ keywordArgs){
		//	summary:
		//		Given an item, this method loads the item so that a subsequent call
		//		to store.isItemLoaded(item) will return true.  If a call to
		//		isItemLoaded() returns true before loadItem() is even called,
		//		then loadItem() need not do any work at all and will not even invoke
		//		the callback handlers.  So, before invoking this method, check that
		//		the item has not already been loaded.  
		// 	keywordArgs:
		//		An anonymous object that defines the item to load and callbacks to invoke when the 
		//		load has completed.  The format of the object is as follows:
		//		{
		//			item: object,
		//			onItem: Function,
		//			onError: Function,
		//			scope: object
		//		}
		//	The *item* parameter.
		//		The item parameter is an object that represents the item in question that should be
		//		contained by the store.  This attribute is required.
		
		//	The *onItem* parameter.
		//		Function(item)
		//		The onItem parameter is the callback to invoke when the item has been loaded.  It takes only one
		//		parameter, the fully loaded item.
		//
		//	The *onError* parameter.
		//		Function(error)
		//		The onError parameter is the callback to invoke when the item load encountered an error.  It takes only one
		//		parameter, the error object
		//
		//	The *scope* parameter.
		//		If a scope object is provided, all of the callback functions (onItem, 
		//		onError, etc) will be invoked in the context of the scope object.
		//		In the body of the callback function, the value of the "this"
		//		keyword will be the scope object.   If no scope object is provided,
		//		the callback functions will be called in the context of dojo.global().
		//		For example, onItem.call(scope, item, request) vs. 
		//		onItem.call(dojo.global(), item, request)
		if (!this.isItemLoaded(keywordArgs.item)) {
			throw new Error('Unimplemented API: dojo.data.api.Read.loadItem');
		}
	},

	fetch: function(/* Object */ keywordArgs){
		//	summary:
		//		Given a query and set of defined options, such as a start and count of items to return,
		//		this method executes the query and makes the results available as data items.
		//		The format and expectations of stores is that they operate in a generally asynchronous 
		//		manner, therefore callbacks are always used to return items located by the fetch parameters.
		//
		//	description:
		//		A Request object will always be returned and is returned immediately.
		//		The basic request is nothing more than the keyword args passed to fetch and 
		//		an additional function attached, abort().  The returned request object may then be used 
		//		to cancel a fetch.  All data items returns are passed through the callbacks defined in the 
		//		fetch parameters and are not present on the 'request' object.
		//
		//		This does not mean that custom stores can not add methods and properties to the request object
		//		returned, only that the API does not require it.  For more info about the Request API, 
		//		see dojo.data.api.Request
		//
		//	keywordArgs:
		//		The keywordArgs parameter may either be an instance of 
		//		conforming to dojo.data.api.Request or may be a simple anonymous object
		//		that may contain any of the following:
		//		{ 
		//			query: query-object or query-string,
		//			queryOptions: object,
		//			onBegin: Function,
		//			onItem: Function,
		//			onComplete: Function,
		//			onError: Function,
		//			scope: object,
		//			start: int
		//			count: int
		//			sort: array
		//		}
		//		All implementations should accept keywordArgs objects with any of
		//		the 9 standard properties: query, onBegin, onItem, onComplete, onError 
		//		scope, sort, start, and count.  Some implementations may accept additional 
		//		properties in the keywordArgs object as valid parameters, such as 
		//		{includeOutliers:true}.         
		//
		//	The *query* parameter.
		//		The query may be optional in some data store implementations.
		//		The dojo.data.api.Read API does not specify the syntax or semantics
		//		of the query itself -- each different data store implementation
		//		may have its own notion of what a query should look like.
		//		However, as of dojo 0.9, 1.0, and 1.1, all the provided datastores in dojo.data
		//		and dojox.data support an object structure query, where the object is a set of 
		//		name/value parameters such as { attrFoo: valueBar, attrFoo1: valueBar1}.  Most of the
		//		dijit widgets, such as ComboBox assume this to be the case when working with a datastore