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Articles by Vrundesha Joshi
Page 2 of 22
Can a user disable HTML5 sessionStorage?
Yes, users can disable HTML5 sessionStorage in their browsers. When disabled, attempts to use sessionStorage will either throw errors or fail silently, depending on the browser implementation. How Users Can Disable sessionStorage Different browsers provide various methods to disable DOM storage, which affects both localStorage and sessionStorage: Firefox Type "about:config" in the address bar and press Enter Search for "dom.storage.enabled" Right-click and toggle to "false" to disable DOM Storage Chrome Go to Settings → Privacy and security → Site Settings Click "Cookies and site data" Select "Block third-party cookies" or "Block all cookies" ...
Read MoreWhat is JavaScript garbage collection?
JavaScript automatically manages memory allocation and deallocation through a process called garbage collection. When you declare variables or create objects, JavaScript allocates memory for them. The garbage collector then identifies and frees memory that is no longer needed by your application. How Garbage Collection Works JavaScript's garbage collector runs automatically in the background, scanning memory to find objects that are no longer reachable or referenced by your code. When these "orphaned" objects are found, their memory is freed up for reuse. Mark-and-Sweep Algorithm The most common garbage collection algorithm in modern JavaScript engines is the mark-and-sweep ...
Read MoreHow to do basic form validation using JavaScript?
JavaScript provides a way to validate form data on the client's computer before sending it to the web server. This improves user experience by catching errors immediately and reduces server load. Basic form validation includes checking that all mandatory fields are filled in and that data meets specific format requirements. It requires looping through each field in the form and validating the data. Basic Validation Methods Form validation typically checks for: Empty required fields Data format (email, phone, zip code) Data length constraints ...
Read MoreHow to search and display the pathname part of the href attribute of an area with JavaScript?
To get the pathname part of the href attribute of an area in JavaScript, use the pathname property. This property extracts just the path portion from a URL, excluding the protocol, domain, and query parameters. Syntax areaElement.pathname Example You can try to run the following code to display the pathname part of an area element's href attribute. ...
Read MoreHow can I delete all cookies with JavaScript?
To delete all cookies with JavaScript, you need to iterate through existing cookies and set their expiration date to the past. JavaScript doesn't provide a direct method to clear all cookies at once, so we must delete them individually. How Cookie Deletion Works Cookies are deleted by setting their expires attribute to a past date. When the browser sees an expired cookie, it automatically removes it from storage. Method 1: Basic Cookie Deletion This approach splits the cookie string and deletes each cookie by name: function deleteAllCookies() { var cookies ...
Read MoreHow to use JavaScript to set cookies for homepage only?
Setting cookies for a specific page like the homepage requires checking the current page URL before creating the cookie. This ensures the cookie is only set when users are on the designated homepage. Understanding the Approach To restrict cookie setting to the homepage only, we need to: Get the current page URL using window.location.pathname Check if the current page matches our homepage criteria Set the cookie only if the condition is met Example: Setting Cookies for Homepage Only ...
Read MoreHow to create a session only cookies with JavaScript?
Session cookies are temporary cookies that expire when the browser session ends (when the user closes the browser). Unlike persistent cookies, they don't have an expiration date set and are automatically deleted when the browser is closed. Creating Session Cookies To create a session cookie in JavaScript, simply omit the expires or max-age attribute when setting the cookie: // Session cookie - no expiration date document.cookie = "sessionUser=johnDoe; path=/"; // Another session cookie with additional attributes document.cookie = "tempData=someValue; path=/; secure; samesite=strict"; console.log("Session cookies created"); console.log("Current cookies:", document.cookie); Session ...
Read MoreUIWebView HTML5 Canvas & Retina Display
When working with HTML5 Canvas on retina displays in UIWebView, images may appear blurry due to pixel density differences. Here's how to properly handle retina displays for crisp canvas rendering. The Retina Display Problem Retina displays have higher pixel density (devicePixelRatio > 1), but Canvas elements default to standard resolution, causing blurry images and drawings. Solution: Scale Canvas for Retina The key is to scale the canvas context and adjust its internal dimensions to match the device's pixel ratio: var canvas = document.getElementById('myCanvas'); var context = canvas.getContext('2d'); var width = 300; ...
Read MoreHow to edit a JavaScript alert box title?
It's not possible to edit a JavaScript alert box title due to security restrictions in web browsers. The native alert() function creates a modal dialog with a predefined title (usually "Alert" or the domain name) that cannot be customized. To create custom alert boxes with editable titles, you need to use alternative approaches like custom JavaScript modal dialogs, CSS frameworks, or specialized libraries. Why Native Alerts Can't Be Customized Browser security policies prevent websites from modifying the alert dialog's appearance to avoid phishing attacks and maintain user trust. The title always shows the browser's default text or ...
Read MoreWhat is the use of JavaScript eval function?
The JavaScript eval() function executes a string as JavaScript code. While powerful, it's generally discouraged due to performance and security concerns. Syntax eval(string) Parameters string: A string representing a JavaScript expression, statement, or sequence of statements. Return Value Returns the completion value of evaluating the given code. If the completion value is empty, undefined is returned. Basic Example var a = 30; var b = 12; ...
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