Infoq interview: using HTML5 to develop mobile Web Applications

Dylan schiann is the co-founder of the dojo Foundation. With this in mind, I think that he is the leader in Web development. In particular, the value of open web he advocates is not necessarily accepted by business groups. Although it is difficult to be neutral, it can also serve as a reference for predicting the development path. I sorted out the following articles for interviews. Article address: http://www.infoq.com/interviews/mobile-web-h5-js.

I. Old technologies.
From the very beginning, mobile devices are simple at the beginning: black and white screens are controlled by a keyboard at a speed of 9 to bps. In this environment, the so-called WAP/WML Internet access is only one of the various functions. Consumers also think that the Internet is dispensable, although it is not to say that the chicken ribs mean rejection, after all, it is also a new thing, or think of it as an ornament, so there is no "User Experience ".

In the wireless surfing process that has evolved over the past decade, users and developers have realized that this is only the beginning and not yet mature. However, as the consumption level increases and the user demand increases explosively, such a mobile device has long been unable to meet new adjustments, and it should be a technical upgrade. If the designers of various vendors are still at the html3/4 version level (WML is actually only HTML-based extension), they can only parse WML/html, script is not supported or a slow Script Engine is provided. This is not a model that is acceptable to consumers or even general consumers.

I personally feel that the connection between the terminal and the gateway is not mentioned here. Of course, it is another layer of content, which is highly related to hardware factors and belongs to GPRS, edge, and CDMA.

2. developer learning curve.

The market is also huge, so developers should be ample, And the development environment and conditions should not be too vigorous, so developers should be discouraged. Aside from talking about j2e-c/Flash Lite, because they differ greatly from the APIs of the desktop program, only the same syntax is left, which is not enough to attract those who are familiar with desktop program development. This group of people is an important development force. I would like to ask who started learning the desktop API? I will try again to ask whether or not I can ignore desktop. If I use the technology I already know, I can develop new businesses and use them again on another day, isn't it easy? Conversely, if objective C, C, Java, or Windows
Moblie can only develop mobile apps. For many new developers, the experience is not enough, and the development efficiency is naturally poor.

Of course, the above is only the subjective intention of the developer. What are the objective conditions? The answer is "embracing standards". Is the standard the "most objective? Oh, good faith ...... What is the standard? Open Web standards. Specifically, the APIS we face are browsers and mobile browsers, such as WebKit, Mozilla browsers, opera mobile browsers, and even Microsoft's ...... And so on. HTML5 first changes a batch of new tags, which have the same significance and value for mobile devices or common browsers. I personally think that, based on the three-layer web design, the role played by HTML as the presentation layer remains unchanged, but the new HTML5 will be inserted into the function of "presentation layer. In addition, it is important to constantly emphasize that, as a standard implementation version, its cross-platform and write
Codes once run everywhere should be undoubtedly supported by such features, otherwise the standard will be meaningless.

Isn't it very attractive to transfer the technology and experience of web development to mobile platforms by embracing standards? However, do different models have different hardware versions, different software versions, different platforms, and code run well?

Taking WebKit as an example, different manufacturers may add or delete some functions on the basis of WebKit. As a result, although WebKit is used as a browser, it may not make your technology run too well, not to mention that "everything is perfect. In this way, a javascript API is required for various mobile platforms. Considering the differences between different models is indeed a headache like trying to solve cross-browser problems. Fortunately, as long as you let the API solve the problem, you don't have to write the browser if-else code to check which one is really painful. Of course, technical developers who are not supported should be clear about what it is, for example, details such as support for SVG, support for canvas, and support for css3. In addition, using the server to solve the compatibility problem is also a solution, that is, dynamic generation of specific browser code. The advantage is that the degree of optimization is high and the code redundancy rate is relatively low.

One is distributed remote storage and the other is local storage. Dylan believes that either solution is a fast and mature technology.

Iii. Introduction of HTML5

For the hot topic nowadays, Flash VS HTML5 and Dylan put forward their own views, he believes that flash can survive in the web world only when it has a revolutionary change (see Dylan's blog can flash thrive), and from a purely technical perspective, question why Adobe does not simply use HTML in flex, but follows its own system as if it is away from standards.

HTML5 makes a sublimation of the valuable experience and wealth accumulated by the development of Web standards over the past decade. This is technically the case. However, whether the market accepts this is another matter. In fact, html4/4.2 is already a very old technology and has never been upgraded for so many years.

What is the practical significance of HTML5 for mobile devices? One of the most practical options is the support of CSS effects, animation and deformation effects, making "pages" more lively, and Web sockets that can greatly reduce network latency. It is a native socket solution. Real-time online chat requires Web sockets.

Sometimes reform cannot be achieved overnight. In other words, how can we gradually improve? Many mobile browsers are still incompatible with HTML5. Can some technologies use other methods to achieve HTML5 functions? If it is a Form or some new semantic elements, it is easier to do. You can use JavaScript to simulate HTML5 features. If it involves video and audio, you can still use flash to perform compaction. Since we talk about vidoe/audio, we can't help but talk about the current codec competition (Flash/h264 raw/Ogg theora). I still don't know what each family has.

Support for development tools. Development tools should not only include how HTML5 is supported, but also integrate the support of development languages. We need a mature code editing environment, a mature simulator, and a mature IDE.

4. Notes

In a project, if you want to include the list of supported platforms from PC, iPad/iPhone to Android, what experiences can be used for reference? Dylan replied that the requirements for different platforms should be clarified. Dylan is a Web-based professional who first compares Web with mobile platforms and uses familiar content as the starting point. He said that some knowledge points considered in the Web can be ignored on mobile devices, such as dragging (dd). Some are often used by mobile devices, but the Web is treated differently, such as local storage access, camera control, and GPS access. In the end, Dylan also talked about technologies such as 3D rendering-technologies that are impossible or not easily achieved by Web and mobile devices at this stage.

Related Projects: phonegap/eventninja (by uxebu ).