This document provides an overview of JavaScript basics including primitive and object data types, conditions and loops, DOM manipulation, events, scope, jQuery, closures, and more. It covers key concepts such as strings, numbers, Booleans, objects, arrays, functions, if/else statements, for loops, document object model trees, getting and manipulating DOM nodes, event handling, adding event listeners, global versus local scope, callbacks, prototypes, and single-threaded execution.

1. JavaScript Basics
Ravi Kumar Hamsa

2. Primitive Data Types
• String
• Number (Integer/Float)
• Boolean
• null
• undefined
• Regex

3. Introduction
Fully dynamic
not secure

4. Object Data Types
• Object
• Array
• Date
• Function

5. Conditions and Loops
• if
• while
• do while
• for
• switch
• == v/s ===

6. Arguments Passing
primitive data types passed by value
object data types passed by reference
there is no way you can change it

7. DOM Tree
window
document
head
body
div
p
...
...

8. Finding DOM node/s
document.getElementById (single node)
document.getElementsByTagName(html
collection)
document.getElementsByClassName(html
collection)
document.querySelector (single node)
document.querySelectorAll (html collection)

9. Common Node Properties
nodeName
childNodes
firstChild
lastChild
attributes
innerHTML
...
...

10. DOM Manipulation
• innerHTML
• outerHTML
• createElement
• appendChild (?existing element)
• removeChild
• setAttribute
• removeAttribute

11. DOM Events
click
mouseenter
mouseleave
mousedown
mouseup
keyup
keydown
window.resize
bubbling v/s capturing

12. Adding Event Listeners/Handlers
• setting attribute in html
(onclick="jsFunction()")
• setting attribute in JS (el.onclick=function(){})
• addEventListener/attachEvent

13. Scope of Variables
• var keyword
• default global scope
• var placement in function
• this keyword
• execution scope in callbacks
• Function.call and Function.apply

14. JQuery
DOM Manipulation
adding/removing classes
setting style
creating nodes
Adding Event Handlers (delegating events)
Ajax Calls
Deferred

15. crossdomain data loading
iframes
flash
JSONP
CORS

16. Closures
what is closure
ajax callbacks
setTimeOut callbacks
scope chain

17. Single Threaded Execution
JavaScript runs on single thread
At any time any one expression is being
evaluated
examples

18. prototype chain
__proto__
inheritance
variable resolution
performance considerations