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JAVASCRIPT Snippets.

Validate an IPv4 Address

Learn how to use a regular expression in JavaScript to accurately validate if a given string represents a valid IPv4 address, ensuring correct octet ranges.

Normalize Whitespace: Replace Multiple Spaces

Learn to clean up user input or text content by using a simple JavaScript regex to replace consecutive whitespace characters with a single space.

Extract All Numbers (Integers & Floats) from a String

Learn to extract both integer and floating-point numbers from a text string using a versatile JavaScript regular expression pattern and convert them to numeric types.

Extract All URLs (HTTP/HTTPS) from a String

Learn to efficiently extract all complete HTTP or HTTPS URLs, including subdomains and paths, from any given string using JavaScript regular expressions.

Validate International Phone Numbers with Optional Country Code

Implement a robust regular expression in JavaScript to validate international phone numbers, supporting optional country codes, spaces, hyphens, and parentheses.

Parse Structured Log Lines into Key-Value Pairs

Learn to parse structured log entries, like access logs, into easily accessible key-value objects using JavaScript's regex capture groups and `matchAll`.

Convert BBCode to HTML for Rich Text Display

Transform BBCode tags like `[b]`, `[i]`, and `[url]` into their corresponding HTML elements (`<strong>`, `<em>`, `<a>`) using JavaScript regex replacement.

Extract All Image `src` Attributes from an HTML String

Efficiently find and extract all image `src` attribute values from a given HTML string using JavaScript regular expressions and `matchAll`.

Modifying DOM Element Styles and Classes

Discover how to programmatically change an element's CSS styles and manipulate its class list using JavaScript for dynamic visual updates.

Implementing Event Delegation for Dynamic DOM Elements

Optimize event handling for multiple or dynamically added elements using event delegation, attaching a single listener to a parent element.

Efficiently Traversing the DOM Tree with JavaScript

Master DOM traversal by learning to navigate between parent, child, and sibling elements using JavaScript properties like `parentElement`, `children`, and `nextElementSibling`.

Reading and Setting Form Input Values and States

Learn to effectively interact with HTML form elements, covering how to get and set input values, manage checkbox/radio states, and handle select options.