Introduction to some new HTML5 draft features

The html4.x version has not yet been released to support new businesses since it was officially released in 1999. The HTML5 draft release has given us new hopes, it is estimated that HTML5 will be gradually implemented in various browsers in the next few years. For example, IE8, which is currently being developed, is said to support some HTML5 features, such as cross-document transfer and client-side storage APIs, network Connection detection and some features of the forward/backward stack; of course Firefox will certainly support it, as shown in figure 3. version X already supports some of the features of offline cache in HTML5.

The following briefly introduces how to completely change our current web development methods and business features:

• Persistent storage. Both key/value and a SQL database are supported.

This feature allows web applications to support local data storage, not only for the current cookie data storage, but also for storing more data on the client.

• An API that enables offline Web Applications

Common resources can be cached on the client's local hard disk to reduce the traffic and pressure on Web servers.

• Drag & Drop API in combination with a draggable attribute.
• Network Connection API.

It enables web applications to communicate with each other in the LAN, maintains a two-way communication (TCP/IP) with the Web server, and supports the P2P application mode. In this way, the browser supports persistent connection with the Web server, so that Web applications can regularly obtain data on the Web server without re-establishing the connection. In addition, because UDP Communication in the LAN is supported, UDP-based applications can be used in the LAN.

• API that exposes the history and allows pages to add to it to prevent breaking the back button. (This API has the necessary security restrictions in place .)

Allows APIs to call forward/backward functions. functions such as registration and map can enhance user interaction experience based on this feature.

• Cross-document messaging.

Cross-Origin document message calls. Due to security factors, cross-origin documents cannot be interacted with each other, that is, cross-site scripts cannot be executed. This feature in HTML5 breaks this restriction and allows documents between different sites to communicate with each other.

• Server-sent events in combination with the new event-source element.

Currently, the HTML standard does not allow the Web server to actively communicate with the Web Client. Therefore, for example, the stock information update method, the Web Client can only regularly call the server to refresh the webpage content, and the data cannot be updated in real time. The server-sent events feature in HTML5 solves this problem. When an event is updated on the server side, the server can push the event to the subscribed Web Client, greatly enhancing the instant effect, when there is no event update, the Web client does not need to be notified, and the Web client does not need to go round-robin events, reducing the pressure and traffic on the server. This feature also makes browser-based instant communication easier and more real-time.

• Notification API to alert the user to new information, such as new e-mail messages in an e-mail application.

This feature allows the source web server to send notifications to the Web Client, such as sending email Arrival notifications. For example, if you receive an email from example.com, mail.example.com will also receive a message. Therefore, when the browser opens the portal.examle.com webpage, you can receive an email notification from mail.example.com, allows users to view new mail Information in the browser instantly.