Inheriting the previous 5 new jQuery.Ajax() examples (jQuery 1.9), I want to record the changes brought about by using the Promise interface of jQuery .Ajax() 1.9 (some of which can be classified as advantages).
-
Name: Apparently, the name has been changed,
success
->done
,error
->fail
,complete
,always
-> . - Deferred: Deferred Promise can be bound to anywhere in the application, resulting in increased flexibility and reusability.
-
Callback order:
fail
The callback order is: 1.done
, 2.always
, 3. . This is the standard order. -
Multiple callbacks:
.always(), .always(), .always()
You can specify any number of callbacks of the same type. For example, , all of this will be fired when the Ajax request returns and completes. - Parameters: (The original text has not been explained in detail, omitted here)
-
Chenge Call:
.then()
Starting with jQuery 1.8, you can use the function to chain Ajax requests. See the example below. -
Combination:
.done()
You can combine.fail()
and.then()
into . See the example below.
// 旧的 complete 函数 complete Function(jqXHR jqXHR, String textStatus) // 新的 done 函数 jqXHR.done(function(data, textStatus, jqXHR) {});
Source: jQuery.Ajax API If you find that I have missed something else, feel free to comment.
Combining .done() and .fail() into .then()
done()
You can combine the fail()
and then()
functions into a
var promise = $.ajax({ url: "/myServerScript" }); promise.then(mySuccessFunction, myErrorFunction);
Source: Deferred and Promise in jQuery, chained Ajax request
Start chain call from jQuery 1.8 then()
then()
Starting with jQuery 1.8, you can call the promise1
functions in a chain order. In the following code, first run getStuff
, after successful parsing, run
var promise1 = $.ajax("/myServerScript1"); function getStuff() { return $.ajax("/myServerScript2"); } promise1.then(getStuff).then(function(myServerScript2Data) { // 两个 Promise 都已解析 });
Each callback function will receive the result of the previous asynchronous function. For Ajax, that is the returned data.
Use .when() as Promise
.when()
You can use .done()
to assign a Promise callback function, i.e.
var container = $("#mycontainer"); $.when( function () { return $.Deferred(function (dfd) { container.fadeOut('slow', dfd.resolve); }).promise(); }(), $.ajax({ url: 'Path/To/My/Url/1', type: 'POST', dataType: 'json' }), $.ajax({ url: 'Path/To/My/Url/2', type: 'POST', dataType: 'json' }) ).done(function (x, data) { container.html('Your request has been processed!'); container.fadeIn('slow'); });
As you can see, we pass three promises to $.when, one for fade out animation and two for Ajax operations.
- The first parameter is a self-executing anonymous function that creates the Deferred handler and returns a Promise. In the $.Deferred callback, the
dfd.resolve
function is passed to the callback parameter offadeOut()
, which means that once the animation is completed, Deferred will be parsed. - About the two other parameters we pass to $.when, since the result of $.ajax is a jqXHR object that implements Promise, we just pass the returned value as is.
Source: Always keep your (jQuery) Promise, FAQs about the advantages of jQuery 1.9 AJAX Promise interface
What are the main advantages of using jQuery 1.9 AJAX Promise interface?
The main advantage of using the jQuery 1.9 AJAX Promise interface is that it can handle multiple AJAX requests simultaneously. This feature is especially useful when you need to perform multiple AJAX requests and want to perform certain operations only after all requests have completed. The Promise interface provides a method to aggregate multiple AJAX request results and execute callback functions until all requests are completed. This makes the code easier to read and manage.
(The answers to the following questions are the same as the original text, but the wording has been slightly adjusted to maintain the original text.)
How to improve error handling on the jQuery 1.9 AJAX Promise interface?
jQuery 1.9 AJAX Promise interface improves error handling by providing a unified way to handle errors. Without writing separate error handling code for each AJAX request, you can use the Promise interface to handle all errors in one place. This not only simplifies the code, but also makes the code easier to maintain and debug.
Can I use the jQuery 1.9 AJAX Promise interface with other versions of jQuery?
Yes, you can use the jQuery 1.9 AJAX Promise interface with other versions of jQuery. However, note that the Promise interface was introduced in jQuery 1.5, so it does not work with earlier versions. Additionally, some features of the Promise interface may not be available in later versions of jQuery, so it is always recommended to check the jQuery documentation for compatibility issues.
jQuery 1.9 How does the AJAX Promise interface compare to other methods that handle AJAX requests?
The jQuery 1.9 AJAX Promise interface has several advantages over other methods that handle AJAX requests. It provides a more structured and organized way to handle multiple AJAX requests, improves error handling, and makes the code easier to read and maintain. However, for beginners, it may be a little more complicated than other methods.
What is the difference between a promise and a Deferred object of jQuery?
The Promise and Deferred objects in jQuery are both used to manage asynchronous operations, but they have different uses. The Deferred object represents an unfinished unit of work, while the Promise object represents the final result of the work. In other words, a Deferred object can be parsed or rejected, while a Promise object can only be fulfilled or rejected.
How to convert a traditional AJAX call to a Promise-based AJAX call?
Converting a traditional AJAX call to a Promise-based AJAX call involves wrapping an AJAX call in a function that returns a Promise object. The Promise object is then parsed or rejected based on the success or failure of the AJAX call.
Can I use the jQuery 1.9 AJAX Promise interface with other JavaScript libraries?
Yes, you can use the jQuery 1.9 AJAX Promise interface with other JavaScript libraries. However, you need to be aware of potential compatibility issues, especially if other libraries also use Promise or similar constructs.
How to use the jQuery 1.9 AJAX Promise interface to handle multiple AJAX requests?
You can use the $.when() function to handle multiple AJAX requests using the jQuery 1.9 AJAX Promise interface. This function takes multiple Promise objects as parameters and returns a new Promise object that resolves when all input Promise objects are parsed.
What happens if the AJAX request fails when using the jQuery 1.9 AJAX Promise interface?
If an AJAX request fails when using the jQuery 1.9 AJAX Promise interface, the Promise object associated with the request will be rejected. You can handle this by attaching the .fail()
handler to the Promise object, which will be called if the Promise is rejected.
Can I use the jQuery 1.9 AJAX Promise interface for non-AJAX asynchronous operations?
Yes, you can use the jQuery 1.9 AJAX Promise interface for non-AJAX asynchronous operations. The Promise interface is a general construct for managing asynchronous operations, so it can be used with any operation that may not be done immediately, such as reading files or querying databases.
The above is the detailed content of jQuery 1.9 .Ajax() New Promise Interface Advantages. For more information, please follow other related articles on the PHP Chinese website!

JavaScript originated in 1995 and was created by Brandon Ike, and realized the language into C. 1.C language provides high performance and system-level programming capabilities for JavaScript. 2. JavaScript's memory management and performance optimization rely on C language. 3. The cross-platform feature of C language helps JavaScript run efficiently on different operating systems.

JavaScript runs in browsers and Node.js environments and relies on the JavaScript engine to parse and execute code. 1) Generate abstract syntax tree (AST) in the parsing stage; 2) convert AST into bytecode or machine code in the compilation stage; 3) execute the compiled code in the execution stage.

The future trends of Python and JavaScript include: 1. Python will consolidate its position in the fields of scientific computing and AI, 2. JavaScript will promote the development of web technology, 3. Cross-platform development will become a hot topic, and 4. Performance optimization will be the focus. Both will continue to expand application scenarios in their respective fields and make more breakthroughs in performance.

Both Python and JavaScript's choices in development environments are important. 1) Python's development environment includes PyCharm, JupyterNotebook and Anaconda, which are suitable for data science and rapid prototyping. 2) The development environment of JavaScript includes Node.js, VSCode and Webpack, which are suitable for front-end and back-end development. Choosing the right tools according to project needs can improve development efficiency and project success rate.

Yes, the engine core of JavaScript is written in C. 1) The C language provides efficient performance and underlying control, which is suitable for the development of JavaScript engine. 2) Taking the V8 engine as an example, its core is written in C, combining the efficiency and object-oriented characteristics of C. 3) The working principle of the JavaScript engine includes parsing, compiling and execution, and the C language plays a key role in these processes.

JavaScript is at the heart of modern websites because it enhances the interactivity and dynamicity of web pages. 1) It allows to change content without refreshing the page, 2) manipulate web pages through DOMAPI, 3) support complex interactive effects such as animation and drag-and-drop, 4) optimize performance and best practices to improve user experience.

C and JavaScript achieve interoperability through WebAssembly. 1) C code is compiled into WebAssembly module and introduced into JavaScript environment to enhance computing power. 2) In game development, C handles physics engines and graphics rendering, and JavaScript is responsible for game logic and user interface.

JavaScript is widely used in websites, mobile applications, desktop applications and server-side programming. 1) In website development, JavaScript operates DOM together with HTML and CSS to achieve dynamic effects and supports frameworks such as jQuery and React. 2) Through ReactNative and Ionic, JavaScript is used to develop cross-platform mobile applications. 3) The Electron framework enables JavaScript to build desktop applications. 4) Node.js allows JavaScript to run on the server side and supports high concurrent requests.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

WebStorm Mac version
Useful JavaScript development tools

mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

SublimeText3 English version
Recommended: Win version, supports code prompts!

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

Notepad++7.3.1
Easy-to-use and free code editor
