So, briefly all languages, no matter what programming language, it is in a human readable format. This is the syntax of the language that follows the programmers. However your computer cannot understand this. All it can understand is what’s called byte code or ones and zeros.
So, now lest understand the browser a little more with each application you have most of the time. It is made of lots of little different applications that controls certain aspects of the program. It looks like one program but it is actually made of many different programs.
"For example, the browser has 3 main programs that we are interested in."
The first program is the DOM interpreter. This will take your hypertext markup language document or HTML document and convert that and display in the browser.
Next, we have another program that is the part of the browser which is the CSS interpreter. This will take the CSS code and style the page and make it look nice.
So, these three major mini programs are called just in time compilers or JIT compilers. So, that simply means that the source code that is downloaded on to the computer is compiled in real time from when the file is successfully downloaded and it’s compiled on user’s computer. So, again it’s just convert it to byte code, so it can be displayed.