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Articles by Rishi Rathor
99 articles
Error Correcting Codes - Reed-Solomon codes
Error-correcting codes (ECC) are mathematical algorithms used to detect and correct errors that occur when digital data is transmitted over noisy communication channels or stored in unreliable media. When bits are transmitted over computer networks, they are subject to corruption due to interference, noise, and various network problems. ECCs can detect the exact number and location of corrupted bits within the algorithm's limitations. They are broadly categorized into two types: block codes and convolutional codes. Reed-Solomon codes belong to the block code category. Reed-Solomon Codes Reed-Solomon (RS) codes are powerful error-correcting codes introduced in 1960 by Irving ...
Read MoreLow-Density Parity Check (LDPC)
Low-Density Parity Check (LDPC) codes are linear error-correcting block codes designed for correcting errors in large block sizes transmitted through very noisy channels. These codes provide excellent error correction performance while maintaining relatively low computational complexity. LDPC codes were developed by Robert G. Gallager in his doctoral dissertation at the Massachusetts Institute of Technology in 1960. Due to their inventor, these codes are also known as Gallager codes. Structure of LDPC Codes An LDPC code is specified by a parity-check matrix that contains mostly 0s and a low density of 1s. The rows of this matrix represent ...
Read MoreSet the language of the linked document in HTML
The hreflang attribute in HTML specifies the language of the linked document. This attribute helps search engines understand the language of the target page and assists browsers in providing appropriate language-based features to users. Syntax Following is the syntax for the hreflang attribute − Link Text The language-code follows the ISO 639-1 standard (two-letter language codes) and can optionally include a country code using ISO 3166-1 alpha-2 format. Common Language Codes Here are some commonly used language codes with the hreflang attribute − Language Code Language Example Usage ...
Read MoreHow to execute the script when the page has finished parsing in HTML?
The defer attribute in HTML allows scripts to execute only after the HTML document has been completely parsed. This ensures that the script runs when the DOM is ready but before the DOMContentLoaded event fires. Syntax Following is the syntax for using the defer attribute − The defer attribute is a boolean attribute that only works with external scripts (scripts with a src attribute). It has no effect on inline scripts. How the Defer Attribute Works When the browser encounters a script with the defer attribute, it downloads the script in ...
Read MoreHow to store a name permanently using HTML5 Local Storage?
The Local Storage is designed for storage that spans multiple windows and lasts beyond the current session. In particular, Web applications may wish to store megabytes of user data, such as entire user-authored documents or a user's mailbox, on the client side for performance reasons. HTML5 localStorage saves string data in the browser and lasts beyond the current session. localStorage stores the data with no expiration, whereas sessionStorage is limited to the session only. When the browser is closed, the session is lost but localStorage data persists. The data won't get deleted when the browser is closed. Here, ...
Read MoreCan Google Analytics track interactions in an offline HTML5 app?
Google Analytics is a freemium analytic tool that provides detailed statistics of web traffic. It is used by more than 60% of website owners. Analytics tools offer insights into website performance, visitor behavior, and data flow. These tools are inexpensive and easy to use, sometimes even free. Yes, Google Analytics can track interactions in offline HTML5 apps, but with specific limitations and considerations. How Offline Tracking Works When an HTML5 application goes offline, Google Analytics stores tracking events in the browser's local storage or SQLite database. After storing these events, it waits until the user comes back ...
Read MoreTo "user-scalable=no" or not to "user-scalable=no" in HTML5
The user-scalable=no viewport meta tag prevents users from zooming on mobile devices. While it creates app-like experiences, it raises important accessibility concerns that developers must consider. What is user-scalable=no? The user-scalable property is part of the viewport meta tag that controls whether users can zoom in and out on mobile devices. When to Use user-scalable=no Consider using user-scalable=no only when creating web applications that need to mimic native mobile app behavior: App-like Interface ...
Read MoreDisplay video inside HTML5 canvas
You can display video inside an HTML5 canvas by using the drawImage() method to render video frames onto the canvas. This technique is useful for applying real-time effects, overlays, or custom controls to video content. Basic Setup First, create the HTML structure with both video and canvas elements: Video in Canvas Your browser does not support the video tag. ...
Read MoreTwo way communication between the browsing contexts in HTML5
Two-way communication between browsing contexts in HTML5 is achieved through Channel Messaging API. This allows secure communication between different origins, iframes, web workers, and windows. The MessageChannel creates two connected ports that can send messages to each other. When you create a MessageChannel, it internally generates two ports - one for sending data and another that gets forwarded to the target browsing context. Key Methods postMessage() − Posts the message through the channel start() − Starts listening for messages on the port close() − Closes the communication ports Basic Syntax // Create ...
Read MoreStoring Credentials in Local Storage
Local Storage is designed for data that spans multiple windows and persists beyond the current session. Web applications can store megabytes of user data on the client side for performance reasons. However, storing credentials requires special security considerations. For secure credential storage, never store actual passwords or sensitive authentication data directly in local storage. Instead, use a token-based approach that minimizes security risks. Secure Token-Based Authentication On successful login, generate a completely random token string unrelated to user credentials. Store this token in your database with an expiry date, then pass it to JavaScript for local storage. ...
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