1-basics

• 01 Intro to JavaScript
• Basic syntax
  • [[#Basic syntax#1. Hello World! Printing to the console|1. Hello World! Printing to the console]]
  • [[#Basic syntax#2. Alert and window prompts|2. Alert and window prompts]]
  • [[#Basic syntax#3. Take user input through html textbox|3. Take user input through html textbox]]
  • [[#Basic syntax#logging|logging]]

01 Intro to JavaScript

• JavaScript is a programming and scripting language used for frontend as well as backend web development
• We use JS along with HTML and CSS to design and make responsive web pages
• JS is an mainly an interpreted language and also a compiled language.

1. Interpreted:
   1. Traditionally, JavaScript was interpreted line-by-line by the browser’s JavaScript engine (V8).
   2. The engine reads the source code, parses it, and executes it directly without prior conversion to machine code.
   3. This interpretation process is relatively straightforward and allows for quick startup times.
2. 1. Compiled: 1. modern JavaScript engines often use a combination of interpretation and compilation techniques to improve performance.
   2. They may initially parse the JavaScript code and then compile it into an intermediate representation.
   3. This representation can be optimized and further compiled (“Just-In-Time” compilation) into machine code for execution.
   4. compilation allows for performance improvements for frequently executed code paths.

Basic syntax

1. Hello World! Printing to the console

// this is our hello world code
console.log("Hello World!");

console.error("there was an error fetching data!");

grouped Logs

console.group("Alphabets");
	console.log("A");
	console.log("B");
	console.log("C");
console.groupEnd()
 
console.groupCollapsed("Alphabets");
	console.log("A");
	console.log("A");
console.groupEnd()

2. Alert and window prompts

alert("hello world");
alert("X-men '97 is awesome!");
 
let name = window.prompt(`enter your name:`);

3. Take user input through html textbox

<input placeholder="username" id="box1" type="text"></input>

let name = document.getElementById("username").value;

logging

console.log("");
console.info("");
console.warn("");
console.error("");
alert("Hello");
 
let name = prompt("Enter name:");
let response =  confirm("Sure?"); 
// returns boolean