Research And Application Of HTML5Local Storage And Offline Caching Mechanisms

With the development of network technology, Web applications with multipleframe, extensive javascript and style sheets are becoming the mainstream. On onehand, these applications make a better experience for the user; On the other hand,they also expose many shortcomings, such as the needs of local storage, poorresponse times, slight waste of traffic flow and not available offline. In order to solvethese problems, the major Internet companies and relevant organizations put forwarda series of technical solutions. Although these technical solutions have partly solvedthe problems above, poor browser compatibility and limited storage capacity stillremain. Therefore, the main purpose of this research is to explore a technical solutionto Web applications without plug-ins, with better client performance and offline use.Firstly, this thesis carries on deep research on the local storage technologyand client caching mechanism that being extensively used, as well as analyzes theirdeficiencies and the reasons for their existence. On this basis, this thesis proposes anew Web application solution based on HTML5local storage and offline cachemechanism, as well as analyzes its feasibility in theory. In this new solution, HTML5is the standard that browsers work with, therefore, applications that based on thissolution have good compatibility without plug-ins. On the local storage, this newsolution use Indexed DB as local database to overcome the limitations of traditionallocal storage capacity. On the client caching, with offline cache mechanism, resourcesspecified can be cached in the local cache to speed up response time andavoid wasteful duplication of resources requested. Finally, thanks to the resources thatcached and the function of local storage, Web applications based on this new solutioncan be accessed offline.To evaluate the actual performance of the new solution, two applications thathave the same functions have been developed, one is based on the Dojo Storage, andthe other is based on the new solution. The experiments of comparing performancebetween these two applications are made, as well as the offline effect of theapplication based on the new solution. By analyzing the experimental results, the performance of new solution is better than the comparison solution, the feasibility andrationality of the new solution is confirmed.