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There are three types of errors in programming: (a) Syntax Errors, (b) Runtime Errors, and (c) Logical Errors. Runtime errors, also called exceptions, occur during execution (after compilation/interpretation). For example, the following line causes a runtime error because here the syntax is correct, but at runtime, it is trying to call a method that does not exist. window.printme(); // printme() method doesn't exist Uncaught TypeError: window.printme is not a function Common Types of Runtime Errors JavaScript throws different types of runtime errors depending on the issue: ... Read More
The throw statement in JavaScript is used to manually create and raise exceptions. When executed, it stops the normal execution flow and passes control to the nearest catch block. Syntax throw expression; The expression can be any value: string, number, boolean, object, or Error instance. Basic Example Here's how to use throw with a simple string message: function checkDivision() { var a = 100; ... Read More
Apple Touch Icons are custom icons that appear when users add your website to their iPhone or iPad home screen. These icons replace the default website screenshot with a professional-looking app-style icon. Basic Apple Touch Icon To add a basic Apple Touch Icon, include this in your HTML section: This creates a bookmark icon when users tap the share button and select "Add to Home Screen" on iOS devices. Multiple Sizes for Different Devices Different Apple devices require different icon sizes. Use the sizes attribute to specify multiple icons: ... Read More
Cascading Style Sheets (CSS) has evolved significantly since its inception. Understanding the differences between CSS versions helps developers choose the right features for their projects and maintain browser compatibility. CSS1 (1996) CSS1 became a W3C recommendation in December 1996. This initial version introduced the fundamental CSS language and a basic visual formatting model for HTML elements. It provided essential styling capabilities like fonts, colors, margins, and borders. CSS2 (1998) CSS2 became a W3C recommendation in May 1998, building upon CSS1 with significant enhancements: Media-specific style sheets for printers and aural devices Downloadable fonts support ... Read More
Adding an active class to the current element allows you to highlight the selected item in navigation menus, tabs, or button groups. This technique uses JavaScript event listeners to dynamically manage CSS classes. Complete Example .btn { border: none; outline: none; padding: 10px 16px; background-color: #6ea2f0; cursor: pointer; color: white; ... Read More
We have an array of numbers that contains some positive and negative even and odd numbers. We need to sort the array in ascending order but with a special requirement: all even numbers should appear before any odd number, and both groups should be sorted internally in ascending order. For example, if we have an array like [-2, 3, 6, -12, 9, 2, -4, -11, -8], the result should be [-12, -8, -4, -2, 2, 6, -11, 3, 9]. How It Works The solution uses a custom comparator function that: Checks if numbers are even ... Read More
Let's say we have the following records of studentId and studentName and want to check a specific student name: const studentDetails = [ { studentId: 101, studentName: "John" }, { studentId: 102, studentName: "David" }, { studentId: 103, ... Read More
JavaScript's built-in functions like parseInt() and parseFloat() only parse numbers from the beginning of a string, stopping when they encounter non-numeric characters. When you need to extract all digits from anywhere within a string, you need a custom solution. The Problem with Built-in Methods Standard parsing methods fail with embedded numbers: console.log(parseInt('454ffdg54hg53')); // 454 (stops at first non-digit) console.log(parseFloat('12.34abc56.78')); // 12.34 (stops at 'a') 454 12.34 Method 1: Loop Through Characters This approach iterates through each character, extracting only digits: const numStr = '454ffdg54hg53'; ... Read More
We are required to write a JavaScript function that takes in a string and turns it into a Mexican Wave i.e. resembling string produced by successive capital letters in every word. For example, if the string is: const str = 'edabit'; Then the output should be the following with successive single capital letters: const output = ["Edabit", "eDabit", "edAbit", "edaBit", "edabIt", "edabiT"]; Method 1: Using String Prototype Extension This approach extends the String prototype with a custom replaceAt method: const str = 'edabit'; const replaceAt = function(index, ... Read More
If you want to write a script with the flexibility to use either W3C DOM or IE 4 DOM depending on their availability, then you can use a capability-testing approach that first checks for the existence of a method or property to determine whether the browser has the capability you desire. Capability Testing Approach The key is to test for specific DOM methods rather than browser names. This ensures your code works regardless of which browser implements which DOM standard. if (document.getElementById) { // If the W3C method exists, use it } else ... Read More