I'm learning web-technologies and programming languages. Start learning about frameworks and other stuff. Looking at Bootstrap Front-End Framework. Some details I don't got about this thing.
On official web page it says you can download compiled and sources of Bootstrap. I don't get it, how can Front-End development be "source" and "compiled", ain't they just scripts that browser interprets?
On
From Extending Bootstrap:
Bootstrap is made with LESS at its core, a dynamic stylesheet language created by our good friend, Alexis Sellier. It makes developing systems-based CSS faster, easier, and more fun.
Since our CSS is written with Less and utilizes variables and mixins, it needs to be compiled for final production implementation. Here's how.
Bootstrap uses LESS files to generate CSS files. The pre-compiled version contains the output from LESS. If you want to modify Bootstrap you'll need the source and then compile the LESS files into CSS.
The term compile is the word LESS uses on their website.
http://lesscss.org/
Doesn't it all compile in the browser upon page load? I'm guessing this means that it was compiled and tested before shipping, but I don't understand why this would need to be advertised.
No, Bootstrap can not run in the browser without the CSS being compiled using LESS.