Jquery 什么是延迟对象

Deferred Object

As of jQuery 1.5, the Deferred object provides a way to register multiple callbacks into self-managed callback queues, invoke callback queues as appropriate, and relay the success or failure state of any synchronous or asynchronous function.

Deferred Methods:

• deferred.done()
• deferred.fail()
  • Add handlers to be called when the Deferred object is rejected.
• deferred.isRejected()
  • 确定延迟对象是否已被拒绝.
• deferred.isResolved()
• deferred.reject()
  • 拒绝延迟对象并使用给定参数调用任何failCallbacks.
• deferred.rejectWith()
  • 拒绝延迟对象，并使用给定的上下文和参数调用任何failCallbacks.
• deferred.resolve()
• deferred.resolveWith()个
  • 解析延迟对象，并调用具有给定上下文和参数的任何DineCallback.
• deferred.then()

Deferred In Action:个

$.get("test.php").done(
    function(){ alert("$.get succeeded"); }
);

$.get("test.php")
    .done(function(){ alert("$.get succeeded"); })
    .fail(function(){ alert("$.get failed!"); });

And it seems that the existing ajax() method callbacks can be chained rather than declared in the settings:

var jqxhr = $.ajax({ url: "example.php" })
    .success(function() { alert("success"); })
    .error(function() { alert("error"); })
    .complete(function() { alert("complete"); });

Working Example From Eric Hynds blog post: http://jsfiddle.net/ehynds/Mrqf8/

jqXHR

As of jQuery 1.5, the $.ajax() method returns the jXHR object, which is a superset of the XMLHTTPRequest object. For more information, see thejXHR section of the $.ajax entry

From JQUERY 1.5 RELEASED:

DEFERRED OBJECTS

随着Ajax的重写

Additionally you can make your own deferred objects using the exposed jQuery.Deferred. More information about this API can be found in the Deferred Object documentation.

Eric Hynds has written up a good tutorial on Using Deferreds in jQuery 1.5.