Notes on javascript .js

Select id/class

document.querySelector('#id')
documnet.querySelector('.class')

es6 new features

• when concatinating two strings, instead of using

 "something " + variable

we can use

`something ${something}` 

Data visualization with d3

<script src="https://d3js.org/d3.v6.min.js"></script>

1. d3 is a JavaScript object
2. d3.select() method select html tags
3. append() method apeends a html tag in a specific tag(selected)
4. text() method write text in a specific tag that is selected

JSON

JSON - JavaScript Object Notation

media type = application/json

extension = .json

fundamentals

Always starts and ends with curly brackets {}. name should be quoted("") in name/value

Data Types

1. Number
2. String (with quote)
3. Boolean
4. Array
5. Object
6. null

tools

https://jsonlint.com/ - JSON validator

AJAX

AJAX - Asyncrhonous JavaScript And XML

fundamentals

No refresh & can request, receive, send Data to a Server. not a programming language - combination of technology within the browser XHR object + JavaScript to connect the request data and the Document Object Model(DOM)