Research On Realization Of Ajax In Browser Of Multifunctional Printer And Simulative Implementation Of Web Layout

This paper is based on my practice in Ricoh Software Technology (Shanghai) Corporation. In Ricoh I participated in the project of MFPBrowser. It is an embedded browser application which is developed on Multifunctional Printer.Multifunctional Printer (The following text we also call it MFP) is office equipment which gathers many functions including print, copy, scan, fax and so on. It's one of the main products of Ricoh Company. Along with the popularization of MFP concept and the change of people's office notion, especially technological progress and improvement of the quality, more and more office users begin to accept Multifunctional Printer. The market of MFP becomes hot. For merchants, this is not only business opportunities, but also means competitions and challenges. So improving the product quality and reducing the product cost is the problem that we have to face.The development of MFPBrowser is an effective method to solve this problem. The cost of applications development on MFP is expensive. Comparing with it, developing a Web application on PC is easier and cheaper. MFPBrowser can act as a medium between these Web applications and MFP. We can customize different servers on PC, and then use them recurring to MFPBrowser. For instance, we can customize a server about scan and print functions, and connect the server with MFPBrowser, and then we can use MFPBrowser and this server instead of the scan and print functions on MFP. So the cost of MFP will be reduced. The performance of MFPBrowser is being perfected and it will be into the maintenance stage in 2008. Presently, in order to enable the pages browsed by MFPBrowser really dynamic, and reduce the load of sever at the same time; the customers put forward a new requirement. They want to realize Ajax function on MFPBrowser.Ajax (Asynchronous JavaScript and XML) is a new favorite hotspot of Web 2.0. In Ajax theory, the user's operation and server's response are asynchronous, and web pages are refreshed partly. These are the biggest characteristics of Ajax. So Ajax can bring the users a good experience.To add new function in MFPBrowser, we must comprehend the module structure of it. It's also the foundation of next step work. In the second chapter of this paper, we presented the analysis about the realizing framework of this browser. This is the precondition of realizing Ajax.Ajax is not a new language or a new technology. Actually, it is the combination of several old technologies in a certain mode. In the common collaboration, those technologies play their respective roles. For the sake of realizing Ajax in MFPBrowser, we investigated it in the third chapter of this paper. We analyzed the roles of every combined technology of Ajax and its use principles. Especially, we analyzed the object XMLHttpRequest which is the popular communications method of Ajax. And then we presented the flow by which applications can use Ajax. This part of the paper analyzed the requirement of realization from the customer's perspective. This is the result which we expect to achieve after realizing Ajax. Actually, MFPBrowser is not to be compared with the mature browsers on PC, like IE etc. So it is unpractical to let MFPBrowser support Ajax as IE.Based on the understanding of the module structure of MFPBrowser and the analysis of Ajax theory, we can do the next step investigation purposefully. Studying how to realize Ajax in MFPBrowser is our original purpose.Then, the paper discussed the investigation about how to realize Ajax in MFPBrowser from the aspect of coding. Three aspects of this problem were emphasized, including implementation of asynchronous request in network modules, Ajax engine which is between server and client, and the changes of layout in web pages brought by instantaneous response. The paper presented the I/O data stream of them, and gave the flow chart analysis, brought forward correlative idea of implementation. Moreover, the paper also presented the cruces of implementation about the XMLHttpRequest object. Firefox. At the same time, we summarized the steps to registering an user-defined object in JS engine of MFPBrowser.The implementation of Ajax will relate to nearly all the modules of browser. Furthermore, because of these modules relating with each other, the workload is considerable if we alter all of them, and the process is also complicated. So the last part of this paper mainly presented the simulative implementation of web layout. The paper carried through particular discussions and analysis from requirement analysis to detail design.In the last chapter, this paper presented the assumption of simulative realization, determined the development environment and requirement of overall layout. Then we described the functional framework that need to be completed and module structure that has been chosen, and made "row" as the unit for layout, solved the problem that how to activate the JS script, analyzed the refurbishing phenomenon of pages which carried on by "block". Then, we designed the layout rules for HTML elements which are the basis of arithmetic for layout. The layout starts with the input of DOM tree that is gained by parsing the HTML page. Here used a local page to replace the network one, so the implementation will be a little easier. The layout module travels the DOM tree according to the sequence of Depth-First. In the meantime, each DOM tree node is converted to a corresponding LineManager data structure. With these data structures and layout rules, we can start layout according to the display flow of HTML elements and position allotment function. At the end of the paper, we listed a fragment of layout result.