Recently we’ve found some users are having difficulty viewing some content on our client’s sites with no real explanation or consistency between user environments. It’s been hard to explain the issue! One piece of consistency between these users is that they’re using Internet Explorer.

The issue was obviously Internet Explorer blocking content, something we initially assumed was down to over-the-top security or privacy settings on the user’s browser. However, with the aid of a detailed user report provided by one of our clients (The Dogs Doodahs), we found that customers were seeing the content filter logo (a small blue ‘no-entry’) symbol in their Address bar within IE this provided us with a good cause for the issue.

What is Internet Explorer’s Content Filter?

The content filter is a feature integrated in newer versions of internet explorer which aims to block certain elements on a website. Its aim is to block potentially harmful content and is commonly used to filter ActiveX controls on websites, but it also ties in to the tracking protection system IE offers.

What is Internet Explorers Tracking Protection?

The tracking protection system within IE is designed to stop certain external tools from tracking the user. It’s sort of a “do not track” feature, automatically controlled client side, without any real user knowledge, based on a set of simple principles:

  • Does this page load anything from an external source?
  • Has this source been loaded on any other sites this user has visited?
  • Has it been loaded more than x times? (where x is 3-30 - a browser setting)
  • If yes, assume this file is tracking the user and block this content

This feature isn’t enabled by default, and doesn’t get enabled during the default installation of Internet explorer. However, with all the recent nonsense over the top “security concerns”, and legislations that have come in regarding cookies; a lot of users have taken to increasing their browser security levels - well beyond what is actually necessary in most cases. The idea of this feature is simply to stop certain 3rd party tools, like Google Analytics, from tracking users and improving their privacy.

Why is Tracking Protection stopping a site or feature from functioning?

As a concept this isn’t that bad an idea, however, it does seem to block any content, not just those files that might be tracking the user. This causes an issue, especially for sources provided on a CDN (Content Delivery Network or Content Distribution Network). 

What is a CDN?

The overall goal of a CDN is to provide high accessibility to content, simultaneously increasing performance of a website, improving overall load times of pages and reducing bandwidth cost. Web developers (and the websites they produce) can use these CDNs to request content commonly used across a range of websites, helping utilise browser cache and removing request load to the server and/or hosting environment.

Why is internet explorer blocking a site’s content?

Internet explorer, with certain security settings therefore undermines the concept of CDNs. It could even stop 3rd party tools from working on a site, not just those used for statistics like Google Analytics, as well as images, pages or other features like:
  • Google Maps
  • Google Fonts
  • Externally sourced images or other content
  • Libraries
  • Or other shared content, etc…

The one thing this was affecting for our clients was the jQuery library, a JavaScript library that aims to simplify client-side scripting. This library has become increasingly popular over the last few years and is very commonly used on websites. The library was obtained from a Google CDN (Google APIs) and being a very common source for this file was being blocked by IE preventing jQuery from loading, this stopped some key functionality on the site from working.

How can I stop Internet Explorer blocking my site and its content

Unfortunately, the only solution we’ve implemented (short of telling users how to change their security settings)  is to stop using CDNs. It’s not a great move since it completely removes the benefits a CDN offers, but it does resolve any issues.

Instead of linking to files hosted on a CDN, like the jQuery library in some instances, we now host the files on our own servers, against the website it’s used on. This means we avoid the blocking criteria of Tracking Protection and the files can be loaded. 

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Dan Peacey

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