If I am going to write a blog titled Peering Behind the Browser, I had better start by defining what exactly it is I mean by a browser. So perhaps the title begs the simple question, “What is a browser?” The search for the answer, we will see, is actually not so simple.
The knee-jerk reaction to the question might be, “Browsers are programs that display web pages like Firefox, Internet Explorer, and Safari.” This brings to mind a similar interaction in Plato’s Theaetetus. In that dialogue, Socrates asked Theaetetus to define ‘knowledge’. Theaetetus replied that knowledge is things that could be learned like geometry, cobbling, and trades. Socrates criticized this answer, pointing out that although those are examples of knowledge, they don’t actually describe what knowledge is. Similarly, the programs listed above are examples of browsers, but fail to explain what one is.
So let’s broaden our definition and say it is a program that remotely accesses data through a network, and renders HTML, JavaScript, and CSS for display to the user. This certainly describes the vast majority of things that a browser does, but does it explain them all? Most people would agree that when they watch a video on YouTube, they are watching it in a browser. However, the underlying technology that YouTube is using is Adobe Flash. If you use a stand-alone Flash player to watch that same movie, does that make the stand-alone player a browser?
This actually becomes far more interesting with the recent offerings of RIA technologies in the last year. Adobe AIR allows exactly these types of stand-alone applications. The ebay Desktop is a perfect example. It uses AIR to provide a desktop-like experience for browsing your ebay account, but displays the same information available at www.ebay.com . Does this make ebay Desktop a browser? To muddy the waters more, AIR applications can be coded in HTML and CSS!
The last data point we will review is JavaFX , an RIA technology produced by Sun. It can allow running Java Applets to be dragged and dropped between programs such as Firefox and Internet Explorer, and the desktop. So if the applet was a browser application while in Firefox, is it still a browser application after it is dragged out and running on the desktop?
I don't actually intend to answer the question, so in a sense I have done no better than Theaetetus did. But in this blog we will be considering all of these technologies as browsers, and we will be peering behind them all to see what lies underneath.
