asynchronous javascript tutorial

Describes the role of jQuery's promise object in JavaScript asynchronous programming, jquerypromise Promise, which can be understood as a desire in Chinese, represents the final result of a single operation. A Promise has three statuses: unfulfilled (not satisfied), fulfilled (satisfied), failed (failed), fulfilled status, and failed status. A desire can be changed to a satisfied or failed State. Once a des

Article Introduction: Ajax and Web service data formats: XML SOAP HTML. When Ajax was created, it was meant to be: Asynchronous JavaScript and XML, asynchronous JavaScript and XML, which is generally the case: First create a network service, such as a PHP page that can pass HTTP get/post parameters, a

The interaction of Web pages is becoming more and more complex, and the asynchronous operation of JavaScript is more and more. such as the common Ajax request, need to respond when the request completes, the request is usually asynchronous, the request in the process of the user can do other operations, will not block the page, this

. So our subject is here.What is the asynchronous operation of JS?JS's execution environment is single-threaded, that is, the program execution down, can only perform a task at a time, the program wants to run down, you must wait for the current task to complete, no matter how long the current task to execute (if the following program rushed out is really difficult to get it).In order to solve the uncomfortable problem of the later procedure and

, and you can continue to perform other browser operations. Make UI operations smoother, but asynchronous programming can also be bad, as the code above, and setTimeout the asynchronous way that you use it, is much more time-consuming than synchronous execution in terms of overall code execution efficiency. At the same time, because it is asynchronous execution,

With the depth of JavaScript learning and the accumulation of practical experience, some principles and underlying things are beginning to be understood. I have seen some articles about JS single-threaded and event loops earlier, but at the time, indefinitely only left a general impression: The JS program in the browser is single-threaded. Well, that's a bit of an impression. There was also some doubt: since it was single-threaded, how was the

In the previous article, we mentioned the implementation of an Async. Operation class for JavaScript asynchronous calls. The callback function is passed through the addCallback method and the callback result is returned through the yield method. Now let's implement this class. Class Structure First, let's build a shelf and list all the variables that need to be used. We need an array to save the callback fu

Problem In AJAX applications, calling XMLHttpRequest is a common case. In particular, client-centric AJAX applications, various operations that need to obtain data from the server are completed by XHR asynchronous calls. However, in single-threaded JavaScript programming, the code style of XHR asynchronous invocation is really out of tune with the usual

Many may have questions about whether conflicts or exceptions occur when Jscex is used together with other class libraries or when syntax is mixed? Let's try it. We use the tab plug-in: lt; script gt; $ (function () {$ ( quot; # tabs quot ;). tabs ({event: quot; mouseover quot ;});... Many may have questions about whether conflicts or exceptions occur when Jscex is used together with other class libraries or when syntax is mixed? Let's try it. We use the tab plug-in: Script$ (Function (){$

This article mainly introduces detailed information about asynchronous JavaScriptPromises. For more information, see. So far, every JavaScript developer and their grandmother may have heard of Promises. If you do not have one, you are about. The concept of promises was proposed by members of the CommonJS team in the Promises/A specification. Promises is gradually used as a method for managing