Note 2: Basics of JS

-

 Setting Up the Development Environment :

  • In order to write a Java script, you need any code editor. There are several code editors are available in the market. like,  VS-Code, Sublime, or Atom.
  • Here , one of them is Vs-Code we can easily download from code.VisualStudio.com

  • another this is I want to install is Node. we can download it from nodejs.org.

  • Technically we don't need Node to run Javascript. because you can run your JavaScript code inside of the browser or Node. but, it is good to install Node in the machine because it is basically used to install third-party libraries.
  • I have installed all things then I had created a new folder on the desktop name as "Basic-JS". and then I open VS-Code. after that, I create a new Html file named Index.Html. also, I have installed live server in vs code. so the browser will get updated as quick when I save my file.



  • So, Basically, we are done with how to get started with the Basics of JavaScript. here I have to explain the required things to developed basic javascript.

First JavaScript program.
  • In order to write JavaScript, we need a script element. there are two places when you can add script elements. we can add Script Tag inside the Head Section or Body Section of HTML.
  • The best practice is to put the script tag inside the body section after completing all the element tags. Because the first reason is browser parses the HTML file from top to bottom so if we put the script tag in the head section there are chances that we have lots of JavaScript code in the head section so the browser may get busy in parsing javascript code and then it won't able to render the page. so, it will create a bad user experience. and another reason almost always codes we have in between this script elements needs to talk to the elements on this web page, for example, we may hide or show any element here in the web page so by adding script tag at the end of the body tag gives confident to render all the elements by the browser.



  • also, we can separate this code in a separate Javascript file. because there are chances that in future we have thousands of lines of code.




Run JS Code in Node.

  • open up the TERMINAL window and write node $filename$. here in my case, I am using 
  • node index.js.






Comments

Post a Comment

Popular posts from this blog

NOTE 1: JavaScript introduction

-
Image
 what is JAVA Script.?     It is the most powerful and widely use language right now. we can create websites, mobile apps, and games with javascript. where does Java script code run.? Java script was originally designed to run only in the browser, each browser has its own Javascript engine that runs the JS. In 2009 a very claver engineer known as Rayan dawn took the open-source JS engine from chrome known as V8 and embedded inside c++ program. and that program is known as a NODE. so, Node is a C++ program that includes google's v8  JS engine. so, now with help with it, we can run JavaScript code outside of the browser. so we can pass our JavaScript code with Node for the execution, so it means we can treat JS like treating in backend service as well as mobile application services. So, a nutshell Javascript code runs inside to the browser or node. browser and node provides runtime environment for our Javascript code. what is the difference between Javascript and ECMAS...
Read more

Note 5: Arrays.

-
Image
Sometimes we have to deal with a list of objects. for example a list of products in shopping carts or selected color from the list. In this kind of situation, we use arrays to store that list. so here is our array of 3 elements if we expend them we will also have an index of each element. and that index determines the position of that element. so, the index of the first element will be 0. next of that will be 1, and so on... and also if we want to access the element of the array we can use index. here in the example, we have selected the first index element which is "Red". As we know JavaScript is a dynamic language so if we change the value of the array the element with different dataType it will change accordingly. and the same rules also apply to the array. also, the objects in the array are dynamic. in other programming languages, we can store the element in the array of the same type but in JavaScript, we can store any type of object in the array. so now we have three st...
Read more

Note 6 : Functions

-
Image
It is a fundamental building block of JavaScript. it is basically a set of statements to perform some tasks and calculate the value. while declaring any function we don't need to add semicolumn at the end like we have declared any variables before. but the functions are more than rather only declaring and calling we can make this more interesting by passing arguments and call that function. Here one thing we have to notice that when we pass in anything in the function call is known as an argument. like here in the above example printMessage('This is the message') the sting here in 'This is the message' is an argument. and a message is written in the function printMessage(message) is a parameter here in printMessage function. the main fundamental things here to work like this is we can reuse the printMessage function. a function may have multiple parameters. the default value of the parameter is undefined. Types of function : or we can write this like this. the funct...
Read more