One of the most important decisions before starting a site design is to decide on the technology used on the site. This is directly related to the needs of the site administrator as well as users when using site facilities
Sufficient knowledge about the technologies used on the site is essential for any web artist. The proper use of any of these technologies when designing a website can make progress and increase success. One of the most important technologies in web designing is E Jacks . In this article, we intend to include the advantages and disadvantages of using it in introducing and expressing its history.
2005 Year resurrection of Jax (Ajax) called. A new technique that reduces the distance between web applications and compiled programs called desktop. The AJAX abbreviation was introduced by the Adaptive Path in mid-February 2005. A title for dynamic and interactive user-side programs that work in the Internet browser environment. Imagine a program like other Windows environment programs but in the heart of the Internet browser. You do not need to wait until you reload the web page when you click on the submit button. Everything happens immediately and quickly.
Imagine being online reading your emails on one of Yahoo’s or Gmail’s sites. Immediately remember that you should send someone a letter. You do not need to leave the page you are reading, or use a trick like right click and the command Open in New windows to open a new window and wait for the page to be reloaded, just want to write a new window. Open your letter.
What is the need to reload all of the partial and secondary information (such as the site logo, name, etc.) that are displayed around the main information? Oh, Jacks do the same for you. Sending a letter will only close the same window and send a few bytes to the destination site, and the program for the year of your mailbox will remain awake and wait for the next command, without shaking or re-displaying. In the world of Back and Forward, the browser almost loses its meaning and application.
The Jacks term was first used by Jessie James Garrett, a programmer from Adaptive Path, in an article titled “A Jacks: A New Approach to Web Applications.”
Why is it asymmetric? Because the combination of these two technologies helps you update a part of a web page without having to (simultaneously symmetrical), this whole page reloads the whole page. This operation is done by an object called XMLHttpRequest, which entered the software many years ago when the introduction of the 4 Internet Explorer browser was introduced, and because of its cool features, all popular and powerful browsers such as Firefox and Opera Support.
If the engine needs data from the server to respond to it, for example, if the data sent for processing, loading new codes, or data retrieval is new, the engine will query those requests in anonymous, usually using XML and Without interrupting the user interaction with the program.
When the web interface uses Ezhex, the user-to-UI connection will never be interrupted. He always sees the software available and ahead of him, and for some time Jacks manages the data sending and receiving operations behind the scenes. It should be noted that Google is leading the way in terms of Jacks’ technology utilization on the Internet, using the Google Groups, Gmail, Google Suggest, and thirty Google Maps software.
Advantages and disadvantages of Ajax
In recent years, the software industry has moved to the production of systems that are independent of the operating system and browser used. A look at the evolution of Web programming languages such as PHP and ASP, and the decline of programmers to technologies such as ActiveX and lava Applet on the user’s side, confirms this point.
In fact, one of the main reasons for the software industry’s attention is to Jacks technology. Unlike technologies such as Macromedia Flash, this achievement does not require the installation of any additional software on the browser, and today there is a necessary platform for implementing Jacks on millions of Web sites and web browsers. Meanwhile, Jacks’ reliance on XML technology is of particular importance. Another important advantage of Jacks technology is its use of the CSS standard. In this way, Jacks can truly be considered a technology related to the interface (and not just the interaction between the client and the server).
However, E Jacks has some disadvantages and these disadvantages are the subject of much discussion in the programming circles on the Internet. One of the issues raised as a bug is the difficulty in changing the user’s habit of using the Back and Forward and Refresh keys in web browsers. One of the problems with web developers is that they should either be accustomed to using the software as little or as much as they write their software, if the user uses these buttons, if desired or unwanted, the software Mistake and error in interpreting the user’s operation.
For example, many e-commerce sites that work on sales of products warn the user when processing an order (that is, right when the final command is sent by the user and still displaying the successful registration order Or failing to register it for an unassigned one, refrain from pressing the Refresh key, and using the Back and Forward buttons in operations that are not readily reversible may confuse the user.
For example, if you delete mail in your inbox, using the Back button will never undo this action. Also, if you add a item to your online shopping cart, pressing the Back button may appear to indicate that the item has been removed from the basket again, but on the side and the server is still in the user’s cart. Since Jacks’ technology converts Navigation or Navigation into a nonlinear process on a site, all these problems may become more acute.
In fact, with the presence of Jacks, the operation of the browser’s history system becomes a daunting issue. Because the programmer must either rebuild the Undo mechanism by adding additional buttons and commands or write the engine and photo so that pressing the Back button automatically triggers the Undo command.
In either case, the programmer’s work is not easy. Of course, tricks and techniques have been devised in this regard too. For example, using the hidden iframe tag in the page interface program that Jackson’s engine can retrieve previous versions of the interface from the browser’s History bin when the Back button is pressed by the user, and again in the motorcycle cycle Jacks enter. This trick is now used in the Google Maps service.
Another problem with Jackson’s technology is the meaninglessness of the concept of Bookmark. Again, the non-linear mechanism of Jacks is problematic. Can I bookmark an ordinary Iranian desktop application and go back to it? Some software such as Photoshop (the Action and History system) do this, but most software is not. In fact, it’s hard to get a photo app from one moment to the next.
This requires a complex repository that keeps both the different interface modes and the different statuses of the interface and the various data states before and after the changes. Of course, I’ve come up with some ideas about AJAX, including the use of anchor in HTML that appears after a sign in a URL.
Another major problem is the connection with E Jacks. This technology is strongly reliant on XML Http Request, and this object is limited by security reasons in new versions of browsers. Because if the server can send this command from any point to any server, then the security threats against the sites will increase. The new restrictions applied in recent versions of browsers have caused the XMLHttpRequest command to fail to interact with another site, other than the web site it came from, which is in conflict with Jacks’s application to the web service.
Of course, solutions have also been proposed to overcome this problem. Such as the XMLHttpRequest object can send a request for dialogue with other sites to a Web server that came from the web page, and this server (which is hosted on the site and is connected to the entire Internet) is an intermediary Act and send requests for the destination site. These Web servers are called Application Proxy.
Another problem with EJacks is that it requires a lot of work from the programmer, and it’s very difficult and time consuming to successfully run an AJAX-based professional interface program. Meanwhile, Jacks make it harder for programmers to make it easy for visitors to work. Yeah, however, has been implemented on a variety of platforms and a variety of tools have been developed to facilitate the work of programmers.
ASP.NET programmers can use the Ajax.NET module if they use the .NET version 101, which is the first implementation of .NET-based and vice versa. Microsoft has introduced the technology in the ASP.NET 2.0 as Atlas.
Java also has several implementations (often with open source) like Ajax Anywhere and AjaxTags. Also, several PHP implementations can be found. The CPAINT and xajax modules are among them. The CPAINT module can also be used for ASP. There are several other modules, such as GeneXus, that have several admissions. For each ColdFusion, Peri, and Python platform, there is at least one known implementation.
- Weak interaction:
One of the weaknesses of the Web environment is its poor interaction with the user. The user must wait until the page is fully loaded. And again, after each click, the information and commands are sent to the server and the user waits for the results again. In this way, a lot of time in the environment and in time is inappropriate and expected. However, the high bandwidth Internet penetration has helped reduce the problem, but the commands and design of the page also became more complex and heavier. Of course Flash technology by Macromedia and Adobe has already somewhat reduced this problem. But there are many reasons to avoid flash on a site that limits the Flash Player’s limit on the user’s PC side and the search engine’s limitations are top notch.
- Having reaction and response:
The classic page design model passes all the form information of that page to the server. The server executes the instruction and returns all the HTML tags again. In most cases, this does not all need work. Because not all page form information
is required to execute the instruction, and not on the user’s side, so that all duplicate information is rebuilt. In fact, the small part of the page should be changed.
For example, when you want to delete a letter from your email list at Yahoo, by choosing the letter you are sending the form containing the information to the Yahoo server. (By pressing the delete button), the Yahoo server scans the form and removes the selected letters, and then rebuilds and returns the entire page. This process is performed on the Google Mail service (Gmail) so that the selected identifier is first sent to the server, and Google will remove it and send the result to the scripts inside the page. It removes that letter and adds an alternate letter to the list to stay constant on the number of displayed messages. This method reduces the amount of information exchanged several times.
The fact that every user clicks a user to wait for a while means that the page designers can not design the interface or appearance of the page the way they want it to. Slowing down pages is the most important limitation, and it’s a way for users to escape. The previous solution to this problem was the Flash application, which was described as a bug. But with the help of Jacks, the designer of the page can make sure that if the user gets a bit of a boredom and the site is fully opened, then there’s no need to send him a full screen again every time he clicks on the mouse. But what he needs to change will be sent to his browser.
- Weakness in use:
In the classic Web model, if an incomplete form is sent and the user refreshes the page again, then we can not say exactly what happens to the program. Suppose the instruction is sent to the user to remove the last record. The results are not returned correctly and the user refreshes the page (F5 key). The same reboot will be posted again to the server and another record will be deleted. Although the .NET Framework has largely solved this problem, it’s still a problem that Jacks are just about to get.
O Jacks was born to solve the problems mentioned above. There was also a reduction in the gap between executive software and the Web environment on the AJAX agenda.
The basic technologies available in AJAX programs are:
- DHTML or Dynamic HTML helps you dynamically update your forms. You use span div and other dynamic HTML elements to mark the HTML document.