JavaScript Tutorial for Beginners: Learn JavaScript in 1 Hour
What is JavaScript, what can you do with it, where does JavaScript code run and what is the
dierence between JavaScript and ECMAScript. The average salary of a JavaScript developer
in the United States is $ 72,000 a year. Every browser has a JavaScript engine and we can
easily write JavaScript code here without any additional tools of course this is not how we
build real-world applications but this is just for a quick demo. In order to write javascript code
you need a code editor there are various code editors out there including Visual Studio code
or yes code sublime text atom. Live server is a lightweight web server that we 're going to use
to serve our web application so install this then you will have to restart Visual Studio code
when you 're done go to the Explorer tab right click index. html and select open with live
server. This will open up Chrome or your default browser and point it to this address that's
where web application is served from now.
JavaScript is a statement a statement is a piece of code that expresses an action to be
carried out in this case we want to log a message on the console. All statements in JavaScript
should be terminated by a semicolon. In JavaScript we can add some description to our code
and this description is ignored by the JavaScript engine. In this lecture I 'm assuming that you
have installed node on your machine if not head over to node. js org and download the latest
version of node. combine these files into a bundle and serve that bundle to the client. Save
the changes back in the browser you can still see the hello world message and that confirms
that our code is still working. A variable is one of the most fundamental concepts in
JavaScript and any other programming languages in programming. We use a variable to store
data temporarily in a computer 's memory. We store our data somewhere and give that
memory location and name and with this name we can read the data at the given location in
the future. The best practice is to use the lead keyword to declare a variable.
The modern best practice is to declare each variable on a single line so we terminate this first
declaration with a semicolon and declare the second variable on new line that 's the modern
best best practice next we 're going to look at constants alright now let 's declare a variable
called interest rate so let interest rate and we set this to 0. 3 now this is the initial value. The
best practice is to use a constant so the value of a variable as the name implies can change
but a constant can not change so here if we change let to Const now interest rate will be a
constant. In situations where we want to have some logic for example if the order is approved
then it needs to be shipped. JavaScript is a dynamic language so unlike other programming
languages the type of these variables will be determined at runtime based on the values that
we assigned to them. In JavaScript unlike other languages we don't have two kinds of
numbers we do n't have floating-point numbers and integers. In es6 we have another
primitive that is symbol and you 're going to learn about that later in the course.
