Building a reliable AJAX application: Part 1th: Building the Front-End

Introduction: Today, Ajax is still the industry's hot word, more and more applications are built using Ajax technology. However, it is not easy to build a good application. This article will focus on building intuitive and easy-to-use Ajax-driven applications.

Ajax is not just a technology. Most developers think it is, and try to prove their point by using languages such as XML and JavaScript. But this view is very limited and ignores the people who pay you: customers, whether they are consultants or your boss (only if you build a satisfactory user base, they will get paid).

Customers are not concerned with technology; they are concerned with how the application behaves externally and how the application responds when they are working through the mouse and keyboard. You can build all the technology in the world into your application, and the application is not necessarily successful, you can build a very simple HTML application, it can work very well. So our goal is to combine technology and usability, which is especially true for Ajax applications.

The promise of Ajax

Understanding what Ajax can offer is important for both developers and users. Whether you define your application as Ajax or not, people have higher expectations for WEB applications, and if you want to satisfy your customers, it's best to understand these expectations.

Availability of

First, Ajax is about usability. Some developers may be surprised because Ajax has given people instant response time, widgets and visual tools, and a variety of GUI elements. These are definitely part of the Ajax experience, but most users-not developers-just find Ajax applications better. They respond as users expect, and the elements of the application-fields, buttons, and images-meet the expectations of the user.

The result is that the application is well used. Users do not need to do a lot of searching, such as where to find zip code fields and how to zoom on a map. If you are designing an Ajax application (and even if you are not designing such an application), you should strive to achieve the same level of usability. User trial and common sense is the best guide, and then we'll discuss some simple ways to make sure your application is available and intuitive.

Responsiveness of

Once you have finished working with availability, you need to deal with the responsiveness of your Ajax applications. At first glance, this seems to be a matter of speed. Ajax applications do not need to submit and refresh pages to server-side programs every time an event occurs, which means a reduction in waiting (at least in theory). However, this part of Ajax features is somewhat of a human factor. In the DSL world, waiting is not a lot. Your mother and grandmother may be using a wired modem instead of dial-up, and if you read this article in your work, it is likely that the network you are using is T1 or T3. Ajax applications are inherently faster, which is hard to understand (what if it's faster and faster?) 10 milliseconds? 100 milliseconds? Do you know what a short time it means? ） 。

However, Ajax applications should be more responsive than traditional applications. It's not just about speed, it's about how the application feels (and that's mostly in usability and interface). For example, suppose you enter your own name and start to choose the color of your favorite Crocs, and the program has plenty of time to perform other tasks while you are doing other things. So your application may get your address, your saved credit card information, and possibly the people you've marked as friends when you visited the online store. All this information can take a lot of time, but if you're busy doing something else and that information has been shown to be available, the application will feel very responsive.

The trick is--we'll discuss this in more detail--when to start making this kind of responsiveness. By arranging fields in your application in a specific way, you know what the user is going to follow. In this way, we can write an Ajax interaction program to take advantage of this process. Keep this in mind, let's start with a little discussion, and we'll go back to that topic with a specific example later.

Unique Class Desktop interface

This is the most acceptable and at the same time the most difficult of an Ajax application features. What we call "feeling" like a desktop application, in many cases, refers to "looking" like a desktop application. My company is using the Zimbra Mail suite, which mimics Microsoft Outlook, and I guess the reason must be that it feels like a desktop application.

There are many different views on this issue. Some people think that the purpose of the WEB is to become a new desktop. You will be using the same application-or its analogues-but these programs will all be online. At first, the rest looks and feels the same as before. Others (I admit that I prefer this camp) think that the Web is a unique space where some places are better than desktop applications and some are worse. The web is its own medium, and applications on the web should be designed separately, rather than simply cloning desktop applications.

In any case, it is clear that Ajax applications can look much better than the 1997 HTML form, when the form has only a large gray Submit form button and a dull "border=1" decoration. So Ajax paradigms require a richer experience, even if many people disagree on how to implement them.