A good application monitoring solution will provide you with the visual representation of the performance, growth, and usage of your AJAX applications. These metrics, along with others, are the critical metrics that need to be checked to ensure no interruptions occurs. Monitoring your applications ensures that your application is delivering you the results it was actually designed for. Below are the few reasons to have your application monitored.

  • Converting leads into customers.  It’s important to create a great rapport between your application and your customer. This is a place where you convert your leads into customers. To ensure that happens, proving a bug-free app is very important.
  • Knowing the customer experience.  To know what your customers experience like what they click, where they spend time on the app, where they mouse hover, etc., is vital to enhance the application to provide a better user experience.
  • Eye on application performance.  Today’s applications are more complex and they have various parts moving back and forth from the server, client, and sometimes third-parties.  The overall application may look fine, but there may be underlying issues at the server and network levels. Addressing those issues is vital.


AJAX: A Quick Overview

AJAX, Asynchronous JavaScript and XML, is a concept, not a programming language, and is independent of the web server software. AJAX is used for creating faster and more interactive web applications.  With AJAX, users can continue to use the application after a trigger because the client program “quietly” makes requests to/from the server behind the scenes. In short, the user will never know that anything was transmitted to the server. AJAX does not need complex triggers. For example, a simple mouse movement can be treated as an event trigger.  Data is stored and sent to the server in XML format using XMLHttpRequest (XHR) objects in the browser. The modern application uses JSON instead of XML as it is easy to use with JavaScript. AJAX has to combine with several elements in order to function:

  • HTML and CSS for presentation
  • JavaScript is called when an event occurs on a page
  • Document Object Model (DOM) represents the structure of XML and HTML documents and how data is interacted with and displayed.
  • XMLHttpRequest is an object provided by the browser’s JavaScript environment, whose methods transfer data between the web browsers and web servers.


Purpose of using AJAX

AJAX is used in applications, typically whenever a small amount of data is stored and retrieved from the web server without postback to the whole page, which is why AJAX is incorporated in many single-page applications (SPAs) to pass JSON objects.  The goals of using AJAX include the following:

  • Faster performing applications.  The main advantage of AJAX is to store and retrieve data by bypassing the webserver known as callbacks. Web services are created to call databases asynchronously. Callbacks make a quick round trip to and from the server without posting the entire page back to the server. By preventing frequent requests on full postback, the network utilization is minimized resulting in quicker operations. As a result, network performance is improved.
  • Avoid wait times.  AJAX makes asynchronous calls to the web server thus allowing the user to continue browsing by avoiding the wait for data to arrive to perform the next action.
  • Reduce server load.  Fewer requests are sent, thus reducing the execution on the server. This reduces the load, thereby saving the bandwidth.
  • User-friendly.  AJAX reduces page postbacks, making applications are more responsive, faster, and more user-friendly.


Application Performance Monitoring

Businesses today have started depending on web applications to grow and expand their sales. An application’s success predominantly lies in end user experience, therefore, providing them with a seamless application is very important.

There are two types of monitoring. Real User Monitoring (RUM), or passive monitoring, records the real user experience and checks for its performances. This type of monitoring has its drawback. It relies on actual users to compile monitoring data.  What if the application is not used by the number of users as expected? How will the web team know about the actual performance?

This is where synthetic, or active, monitoring comes in. Behavioral scripts are generated and are executed frequently to know the availability and performance of the application. If any errors occur, teams can be be alerted to quickly fix any issues. Synthetic monitoring can be done without the presence of the actual users.


AJAX: Disadvantages

In spite of all the AJAX advantages that promote the purpose of using it for dynamic applications, there are certain disadvantages. We’ll discuss a few of them below.

  • Network latency.  Factors like heavy traffic at a particular time, inadequate bandwidth, and Wi-Fi usage, can affect the speed of AJAX calls.  Therefore, frequent monitoring of network, bandwidth, traffic, and rectifying those issues early, can ensure users have a smooth experience.
  • Browser compatibility issues.  Any AJAX calls may work on one browser and not on the another. It is vital to have the AJAX functions consistently work on all browsers. Any new website created or a new feature developed for a web application has to be made compatible across all browsers.  Synthetic monitoring should be employed to test the AJAX calls for persistent functioning of applications across all browsers, especially when frequent updates are done.
  • Security.  Web 2.0 with its maximum usage of AJAX encompassed with JavaScript has made web into a super platform. Consequently, this has also paved the way for a lot of viruses. AJAX functions are prone to security threats.
  • Validation confusion.  Most of the time, it is thought that the validation is done by the other party (client-side or server-side). This confusion leads to neither party implementing the validation properly. This leads to easy insertion of malicious data.
  • Data serialization.  Browsers can evoke AJAX calls and perform data serialization. It can fetch JSON, XML, HTML blocks, feeds, JavaScript arrays and objects. If any of these blocks are intercepted, browsers can be forced to show vicious data.


The Dotcom-Monitor Approach

Dotcom-Monitor can ensure the functionality, performance, and uptime of your AJAX web applications. It’s important to measure HTTP responses, but ensuring that the application renders correctly to the user is of utmost importance.  To do that, the EveryStep Web Recorder is used to record scripts of user actions and and playback/set up monitoring. Additionally, the EveyStep Web Recorder uses a unique content and image validation technology for dynamic applications.  This enables you to match specific keywords and pixel coordinates of images, ensuring the website or web application renders properly, ensuring it looks perfect to the user each time.

These scripts are run at the user-defined frequency (as frequent as every minute), in real browsers, from various global monitoring locations. Once the monitoring device is up and running, users can view the the various JavaScript requests through waterfall charts and performance reports.




Again, it’s important to measure successful HTTP responses, but that doesn’t mean that the page or application rendered correctly in the browser to your customers.  Once the JavaScript-based page or application has loaded, basic monitoring won’t give you any metrics after that, which is why it’s critically important to monitor the elements from a real browser.


Conclusion:  Monitoring AJAX Applications

To wrap up, as AJAX applications become more pervasive, the need to script user behavior and monitor those scripts for errors, is necessary to ensure a great user experience.  Monitoring your applications for user performance and functionality traits has to implemented in order to hold on to your existing customers and to attract new one. Learn more about monitoring dynamic applications, like AJAX, with Dotcom-Monitor.

Try the entire Dotcom-Monitor platform for free.



Image:  By Gengns-Genesis – Own work, CC BY-SA 4.0

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