Summary

Microsoft Internet Explorer 11 (IE11) is the last version of the Internet Explorer web browser from Microsoft. It was released in October 2013 and is being supported by Microsoft until the end of life of Windows 10.

When released in 2013, Internet Explorer was considered the fastest of contemporary web browsers. Now, it is the slowest by a significant margin. There are two main reasons for this:

1. The JavaScript engine that IE11 uses for application functionality is notoriously slow. In industry benchmarking, it comes last in every test, in some cases failing the test completely .
2. The page-rendering performance in IE11 is known to be very slow and unpredictable when calculating positions of items on a page, such as for grids or variably sized boxes. In combination with the slow JavaScript engine, this adds a 50-100% performance penalty on rendering times.

Given that most modern web applications are JavaScript-based, including the FlightGlobal range of products, our recommendation is to use the latest version of a modern browser such as Microsoft Edge, Mozilla Firefox or Google Chrome.

This is not a recommendation we make lightly. However, other large software-as-a-service organisations such as Salesforce are publishing similar advisories.

Details

In the last couple of years, FlightGlobal – like many large organisations – has started to build applications using the latest technologies available in order to create an enhanced experience for users who are using modern, more powerful web browsers. This mainly involves the use of JavaScript frameworks that defer a lot of the user-interface generation and interaction to the browser.

When IE11 was released in 2013, there was little incentive for browser makers to optimise the performance of the JavaScript engine; all focus was on the HTML compatibility of the browser instead. At that time, websites also generated all content on the servers, so the browser could be dedicated to drawing the content of the page, rather than running applications.

Subsequent to this, Google and Mozilla started to refocus on JavaScript performance, amid a drive to push web processing to the browser. IE11 was never part of this push since Microsoft was concentrating on its new browser, Edge.

Now in 2018, the performance of IE11 is so far behind that no amount of JavaScript optimisation will make an application run significantly faster. Because of these factors, FlightGlobal now recommends that users migrate from IE11 to a more modern browser like Google Chrome or Microsoft Edge in order to gain maximum benefit from our product suite.

What does this mean for users who cannot move off IE11?

We will continue to resolve IE11 issues that break core functionality, but, we will no longer resolve issues related to performance and styling.