
JavaScript is used to create client-side dynamic pages. JavaScript is an object-based scripting language which is lightweight and cross-platform.
Javascript First Program:
console.log("Welcome to Stately World");
Tools For JavaScript Programming
There are some tools including frameworks, debuggers, text editors, etc. that will help you code efficiently using JavaScript.
Text Editors
You can use Sublime Text, Notpad++, Visual Code, etc as a text editor.
Browser
You can use any browser for Javascript program. I am listing some browser name below.
Display output in JavaScript
JavaScript can “display” data in different ways:
console.log('Hello World');
document.write()
window.alert()
Getting an element in Javascript:
* getElementByID() * getElementsByClassName() * getElementsByTagName() * querySelector() + querySelectorAll()
Creating things in the documents
* createElement() * createAttribute()
Example: Multidimensional Array
var activities = [ ['Work', 9], ['Eat', 2], ['Commute', 2], ['Play Game', 2], ['Sleep', 7] ]; activities.push(['Study',2]); for (var i = 0; i < activities.length; i++) { console.log(i); var percentage = ((activities[i][1] / 24) * 100).toFixed(); activities[i][2] = percentage + '%'; } console.log(activities.join('\n')); // loop the outer array for (var i = 0; i < activities.length; i++) { // get the size of the inner array var innerArrayLength = activities[i].length; // loop the inner array for (var j = 0; j < innerArrayLength; j++) { console.log('[' + i + ',' + j + '] = ' + activities[i][j]); } }
Object.keys, values, entries
For plain objects, the following methods are available:
Object.keys(obj) – returns an array of keys.
Object.values(obj) – returns an array of values.
Object.entries(obj) – returns an array of [key, value] pairs.