It’s a simple web page!

No it’s not.

Most pages on the web nowadays:

  1. draw content from multiple sources
  2. execute programs (scripts) on your computer, also from multiple sources

What does this mean for you?

Well, for starters it’s important to leave behind the misconception that a web page is a simple thing. There is usually a lot going on in the background that you don’t see. But it’s there. This is how online advertising revenue is generated, and how “advanced” online services operate.

It’s also important to realise that “trust” is a very thorny issue. Visiting the website of (for example) National Geographic shouldn’t be an issue – I mean they’re a respectable business, right? But hang on, on closer examination, look what happens when you visit a single page:

All of a sudden it’s evident that this web page, hosted on  is requesting content from EIGHT (8) different domains, not all of which have an obvious relevance to the web page you are trying to see.

Do you know and trust all of them?

Further, aggregating content from many different domains in one web page usually translated to executing code in your browser, on your computer, from all those different domains you had no idea you were communicating with!

In summary:

All you did was request to see a web page from – which you trust.

Subsequently, and without your express permission or knowledge, your computer was instructed by to download content from,,,,,, and

Your computer also downloaded and executed programs (scripts) from the following domains:,,,,,,, and

I’m only aware of this carnage because of two Firefox addons I use: NoScript and RequestPolicy. But they’re cumbersome to use and require constant adjustments.

Have that in mind next time you catch yourself thinking “I’m safe online because I don’t visit random websites”.

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