Javascript Complete

On Javascript

A webserver and real language:

Old school way (that's still pretty popular)

Webserver (which just serves up pages)
Language (e.g. PHP or ASP) — i.e. a web-specific language



A webserver and real language:

New school way

All in one
e.g. Python's Django

Again, quick review of languages

Quick note on databases

It's a good question. Data storage and retrieval is hard.


The 800lb gorilla.

Once again, why this mediocre language?


(in an infinite bandwidth world, I imagine this would look different)

But why THIS language?

First to market. That's pretty much it.

But why THIS language?

"Because we need interactivity on the web right now, and anything’s better than Flash."

Brendan Eich, Creator of Javascript...

“I was writing something that could be used by people who didn’t know what a compiler was.
They were just going to load it.

“It was like Basic. That was really the pitch….”

“I was under marketing orders to make it look like Java but not make it too big for its britches.
It’s just this sort of silly little brother language, right? The sidekick to Java.”



Client- Side Language.

Meaning, the BROWSER does the work.

Arbitrary, executable code in your browser, all the time.


SO- in PHP (and other server side languages)
- The computer hosting the website does the work.

In Javascript?
- Your computer, the one viewing the website, does the work.

JS Specifics

- Weakly/Dynamically typed
- end statements with a semicolon. Or dont.
- One number type; a 64 bit “double”


Doesn’t have “Classes,” but can have “Prototypes - “

Basically, a creator function with lots of “this” going on.

JS Mechanics

In practice:
Instructions (scripts) on an HTML page that get executed on connection.

But the scripts don’t replace themselves like in PHP, they send instructions to modify other parts of the page as needed.

JS Mechanics

This is done via the DOM, the Document Object Model.

Very similar to how we specified things in CSS, (e.g. tags) except in a “tree” format.

JS Mechanics

JavaScript Object Notation or:

An increasingly popular text data storage format that can do mostly what XML does. Not bad actually. Inspired even easier ones like YAML.

Has it gotten better?

Yes, I think. Almost out of necessity.

But just about EVERYTHING has been replicated, rewritten.

Not only can you theoretically do everything in Javascript, a lot of it is literally "there."

But-- LOTS of wheel reinvention. I mean LOTS

So much so, it's hard to keep up with.

Also, lots of transpiling and other languages etc. etc.

The RUNK problem

The error


Backlinks: FSU Courses:LIS5362:RawSlides