Jquery Lingering objects

The deferred object, introduced in 1.5 in jquery, is a jQuery.Deferred() tool object that creates a chained invocation by invoking a method. It can register multiple callbacks to the callback queue, call the callback queue, and prepare to replace any synchronous or asynchronous function with a successful or failed state.

Deferred.alway ()

When the deferred (deferred) object is resolved or rejected, the add handler is called.

Deferred.always (Alwayscallbacks [, Alwayscallbacks])

Parameter alwayscallbacks type: A function or function array

Example:

1 function () {2   console.log ("$.get completed with success or error callback arguments"); 3 } ); 4 Object {readystate:1}5678 with success or error callback arguments

Deferred.done ()

When the deferred object is closed, the handler is added and the parameter is the same as Deferred.alway ()

Example:

1 functionB () {2Console.log ("Test");3 }4 5 6 varDtd=$.  Deferred (); Creating lingering Objects7 Dtd.resolve (); Changing lingering objects, delaying object resolution8Dtd.done (b). Done (function(){9Console.log ("B is done");Ten }); One  A Test -  -B is done

Deferred.fail ()

Called when a deferred object is rejected

1 var dtd = $. Deferred (); 2 Dtd.reject (); 3 dtd.fail (function() {Console.log ("fail")}); 4 5  Fail

Deferred.resolve ()

Set the lingering object to resolve and execute the callback function;

Deferred.reject ()

Denies lingering objects and executes callback functions;

Deferred.state ()

Determines the current state of a lingering object. This method does not accept parameters and returns only one string for the following three:

Resolved: Indicates that the lingering object is in the resolution state;

Rejected: Indicates that the deferred object is a deny state;

Pending: Indicates that lingering objects have not been resolved;

Deferrred.then ()

The add handler is called when the deferred (deferred) object is resolved, rejected, or still in progress.

Example:

1 functionA1 () {2             varDTD = $. Deferred (); 3Console.log ("AA");4 dtd.resolve ();5             6             returnDTD;7         }8 9 varan=A1 ();Ten  OneAn.then (function() { AConsole.log ("an"); -     }) -  the AA -  -An

Jquery Lingering objects