Java Script Basics
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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.
Java Script Basics
- 1. JavaScript Basics Ravi Kumar Hamsa
- 2. Primitive Data Types • String • Number (Integer/Float) • Boolean • null • undefined • Regex
- 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
- 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)
- 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
- 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