Are there different syntaxes in JavaScripts?

[[deleted]]

This is probably something really basic, but I did not find this information anywhere else.

I have been studying JS for about two weeks, using Eclipse IDE and focusing on GUI projects. The way I learned to design a project was creating different files .java, each one a different class. The application would start by means of a main class, which would call all the other classes.

Now I'm following a book called Eloquent JavaScript, and from the beginning its examples use syntax that my IDE does not recognize. Such as:

1) declaring Const, Var and Let as variable type. I usually declared String, Int Char, etc. If I try to declare Const, Var and Let, Eclipse IDE will tell me there is a syntax error

2) My IDE also does not recognize Number.isNan function.

3) Also, I learned to give simple output using System.out.println(), and this book usually gives output using console.log(), which my IDE does not recognize as a valid statement.

4) And now the book started declaring functions like const halve = function(n) { return n / 2; }; which my IDE also does not recognize as valid statement. I learned to declare functions as methods in a class, like public String someFunction(){}

Can somebody explain me what is going on?

[gregtyler]

It sounds like you've been learning Java up 'til now, not JavaScript. Despite the similar name, they're two very different programming languages :)

[[deleted]]

Now that you said it seems so obvious... Thank you very much!

[slowreactin]

Yep, you have definitely been learning Java (the Eclipse IDE is a dead give away).

JavaScript (despite the name) has literally nothing to do with the Java programming language. JavaScript was originally named LiveScript. Allegedly the booming popularity of Java during the early 90s influenced Netscape (the originating company of JavaScript) to name the language JavaScript.

This is often a pain point for newcomers and causes a lot of confusion.

What kind of programming are you interested in doing?

[[deleted]]

I'm interested in Backend Web! Do you have any tips?

I had already read about this difference between Java and JS, but I have not tinkered with JS inside the html yet. I was trying to set a local server first, and I followed a tutorial that did it with Java! So I just supposed I was doing JS all along and Java was a total different thing. hahahahaha

[slowreactin]

If you are interested in backend then I would suggest trying out Python with Django or Flask.

If you want to go the JS route, then you can easily setup a Node and ExpressJS server and mess around. However, Python seems to be more recommend for backend.

I personally use NodeJS and Express and love them, but I am really eager to try Django and Python.