Latest Javascript Tutorials and How-To's

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How to Prevent Disqus Comments System from Slowing Page Speed & Performance

Loading Disqus' script files and comments on page load can lower down speed and performance of the page, specially in mobiles. A solution would be to use an Intersection Observer to lazily load Disqus.
November 9, 2019
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How to Detect Number of Processor Cores with Javascript

The number of available logical processor cores in the device can be found with the navigator.hardwareConcurrency Javascript property. This number can be useful in knowing how many Web Workers can be executed in parallel.
November 6, 2019
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Javascript KV Storage Introduction Tutorial

KV Storage API is an asynchronous way to save data in the browser using Javascript Promises. Its asynchronous nature guarantees that the performance of the application is not impacted.
November 4, 2019
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How to write Immediately-invoked / Anonymous Async Functions (IIFE)

An anonymous async function can be defined using the Immediately-invoked Function Expression pattern for asynchronous functions.
November 2, 2019
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How to Convert Array to a String in Javascript

A Javascript array can be converted to a string by using the join() method to join elements of the array separated by a given character or string.
October 31, 2019
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How to Create QR Codes in JavaScript

QR codes have become really popular these days. In web pages QR Codes can be generated using the QRCode.js Javascript library.
October 28, 2019
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How to Prevent Form Validation on Page Load & While Typing on Input Field (HTML Constraint Validation API)

The Constraint Validation API validates HTML forms on page load, and while typing on an input field. This seemingly confusing behavoiur to the user can be modified using a bit of CSS and Javascript.
October 26, 2019
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How to Remove Duplicates from an Array using the Set Datatype

Duplicate elements can be removed from a Javascript array using the Set data type. A Set object can be created from the array, and then the Set can be converted back to an array.
October 23, 2019
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How to Assign Default Values to Function Parameters in JavaScript

Function parameters can be initialized with a default value in the parameter list itself using ES6 default parameters.
October 20, 2019
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How to Convert String to Number in Javascript

The Number() method can be used to convert a string containing numeric characters to a number upon which mathematical operations can be done.
October 18, 2019
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How to Check Number is Positive or Negative in Javascript (ES6 Way)

The Math.sign() is a new method introduced in ES6 that can be used to find whether a number is positive or negative or a zero.
October 17, 2019
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How to Get the Integer Value from a Decimal Number in Javascript

The Math.trunc() method can be used to truncate the fractional portion of a number. The number can also be rounded to the next integer using Math.round(), Math.ceil() and Math.floor() methods.
October 15, 2019
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Handling HTML Checkboxes with Javascript

This tutorial explains how to manipulate HTML checkboxes with Javascript. Most of the operations can be performed through the checked property of the checkbox DOM element.
October 7, 2019
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How to Access this in Event Handlers and Callbacks with globalThis Property

The globalThis is a global property referring to the global object. This makes it very easy to access this inside callbacks, event handlers, inner functions etc.
October 6, 2019
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How to Open URL in a New Tab with Javascript

A URL can be opened in a new tab in Javascript using the window.open() method. Both tabs can communicate with each other.
October 3, 2019
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How to Get Values of a Javascript Object with Object.values()

All property values of a Javascript object can be found with the Object.values() method. Only values of own enumerable properties are returned.
October 1, 2019
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How to Get Keys of a Javascript Object with Object.keys()

Keys of a Javscript object can be retrieved using the Object.keys() method. This returns own enumerable property names as an array.
September 29, 2019
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How to Sort an Array of Objects in Javascript

The sort() method can be used to sort an array of objects. A custom callback function can be written that can sort using key(s) of the included objects.
September 24, 2019
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How to Get CSS Values of Pseudo Elements with Javascript

CSS values of a pseudo-element can be retrieved in Javascript using the window.getComputedStyle() method.
September 21, 2019
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How to Get Current Value of a CSS Property in Javascript

The window.getComputedStyle() method can be used to get current values of CSS properties of an element.
September 15, 2019