Many people use the Internet, a realm which used to belong among tech geeks.  However, an ordinary Internet user would have no idea about its minute details, such as the fact that different web browsers use different software such as layout engines.

A layout engine takes a web page's markup languages like HTML as well as its formatting information like CSS, and then displays the formatted content on the screen.  Different web browsers have different layout engines.  For instance, Firefox uses Gecko, while Internet Explorer 7 uses the Trident engine.  Two are among the most commonly-used layout engines, but what are the similarities and differences between the two?

Both have the same goal

As with all layout engines, both Gecko and Trident intend to create a standards-compliant HTML engine that can deal with all kinds of Web pages.  Many websites use other languages aside from the usual HTML such as XML, XHTML, Javascript, and RDF, each demand for a different rendering from the other language. 

A good layout engine should be able to distinguish between markup languages and be able to display the web page without any trace of clutter and incompatibility.

They were created by different groups for different needs

Trident was developed mostly by Microsoft, with an intention of allowing software developers to easily-and freely-add web browsing functionality to their own Window applications. 

Meanwhile, Gecko was first developed by the people behind Netscape before the work was taken over by Mozilla Corporation.  It was intended for other developers to create their own browsers and applications.

Gecko is open-source

The reason why developers can easily create their own applications and even web browsers using Gecko is because it has an open-source license.  Simply put, anyone can use Gecko-and even modify it-without an expressed consent to its makers. 

Meanwhile, Trident is closed-sourced, which means the developers would have to follower a strict set of rules when using, modifying, copying, and republishing the software.

Gecko is perceived today as more superior

Back when the battle of the web browsers was merely confined between Netscape Navigator and Internet Explorer, Netscape was using a layout engine that would become Gecko while Internet Explorer has been using Trident since its introduction of IE4. 

At that time, Netscape was seen as the inferior product because of its slow layout engine and non-compliance to W3C standards, which Internet Explorer was good at.  However, that layout engine was developed further into what is now Gecko, which is being used in Mozilla Firefox. 

Nowadays, the problems that were pointed out on Netscape is not being blamed on Internet Explorer.  Also, Gecko is seen by developers as a superior alternative to Trident because it is cross platform and also lacks many security vulnerabilities that Trident is now prone at.