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Javascript Articles
Page 497 of 534
JavaScript regex program to display name to be only numbers, letters and underscore.
In this article, we will learn the regex program to validate names to contain only numbers, letters, and underscores in JavaScript. Validating user input is essential for maintaining data integrity and security in web applications. JavaScript Regex for Name Validation Regular expressions (regex) are powerful tools for defining patterns to search and validate text. A common validation requirement is ensuring a name consists only of letters (A-Z, a-z), digits (0-9), and underscore (_). To ensure that a name contains only allowed characters, we use the following regex pattern: /^\w+$/ Regex Pattern Breakdown ...
Read MoreJavaScript focus a particular element with div class, not div id declaration?
In this article, we will learn to focus on a particular element with a div class in JavaScript. In JavaScript, setting focus on an element is commonly done using the focus() method, which works with elements selected by class name. What is the focus() method? The focus() method in JavaScript is used to bring a specific element into focus. This means the element becomes active, allowing the user to interact with it, such as typing in an input field or highlighting a section of the webpage. Syntax element.focus(); Here, the element is the ...
Read MoreJavaScript RegExp return values between various square brackets? How to get value brackets?
Extracting values between various square brackets can be done using JavaScript regular expressions. The regular expressions in JavaScript are useful for extracting values enclosed within different types of brackets, such as square brackets ([ ]), curly brackets ({ }), and parentheses "( )". In this article, we'll look at how to use JavaScript's RegExp to find and get content that is inside square brackets easily. Understanding JavaScript RegExp Regular expressions (RegExp) are patterns used to match and manipulate strings in JavaScript. JavaScript RegExp helps you find and get text that is inside specific brackets by using patterns. ...
Read MoreHow to add, access JavaScript object methods?
Adding and accessing object methods are common tasks in JavaScript. JavaScript objects are collections of properties and methods, and the JavaScript methods are functions associated with objects. JavaScript provides various features and ways to add and access object methods. In this article, we will understand how to add or access object methods in JavaScript. Understanding JavaScript Object Methods JavaScript methods are functions associated with objects. They allow objects to perform actions, which is important for creating dynamic and interactive programs. Methods in objects are functions that work with the object's properties. This helps make programming more organized and efficient. ...
Read MoreHow to autofill a field in JavaScript same as another?
Automatically filling a field in JavaScript is a common requirement in web forms, where one field copies the value from another. This feature eliminates the need to write the same information in multiple fields. This is useful in real-life scenarios, such as forms where users enter a permanent address and need to add a temporary address. If both addresses are the same, using the autofill feature, they can automatically copy the permanent address to the temporary address field. This article explains how to create autofill functionality in JavaScript. Core Concept: Copying Field Values The main concept is ...
Read MoreJavaScript algorithm for converting Roman numbers to decimal numbers
For converting a Roman numeral into a decimal number, JavaScript provides simple and efficient ways. Roman numerals are a number system that started in ancient Rome and are still used today in different situations. Converting Roman numerals to decimal (integer) values can be useful in many applications, such as date conversions, numbering systems, or educational tools. In this article, we will see a JavaScript algorithm to convert Roman numerals into decimal numbers efficiently. Understanding Roman Numerals Roman numerals are a number system that uses combinations of letters from the Latin alphabet to represent values. It uses seven letters to ...
Read MoreJavaScript Count characters case insensitive
Counting characters in a string is a common task in programming, especially when analyzing text or creating applications that handle user input. Counting characters in a string without worrying about uppercase or lowercase letters is a common task in text processing and data analysis. JavaScript offers different methods to easily count how many times each character appears, regardless of case. Understanding Case Insensitive Case insensitivity in programming means that a system treats uppercase and lowercase letters as the same. For example, "Hello" and "hello" would be treated as ...
Read MoreHow do you make a button that adds text in HTML \'input\'?
You can make a button that adds text to an HTML input field using JavaScript's document.getElementById() method and event listeners. This approach allows you to dynamically modify input values when users interact with buttons. Basic HTML Structure First, create the HTML elements - a button and an input field: Click to add text Example: Adding Text on Button Click Add Text to Input Click to add "JavaScript" to ...
Read MoreJavaScript fetch a specific value with eval()?
The eval() function in JavaScript allows the execution of code stored as a string. It can be used to fetch specific values dynamically, but be careful, as it can have security risks and affect performance. This article will guide you on how to use eval() to get specific values and why you should generally avoid using eval(). How eval() Works The eval() function takes a string as an argument and evaluates it as JavaScript code. For example: console.log(eval("2 + 2")); // Output: 4 console.log(eval("'Hello' + ' World'")); // Output: Hello World 4 Hello World ...
Read MoreJavaScript code to extract the words in quotations
Extracting text enclosed in quotation marks is a common task in programming, especially when working with strings that include quotes. In JavaScript, strings are a data type used to represent text. A string is a sequence of characters enclosed in single quotes ('), double quotes ("), or backticks (`). JavaScript provides multiple ways to extract text enclosed in quotation marks. This article explains how to extract words or phrases inside quotations from a string efficiently using different approaches. Methods to Extract Quoted Text Extracting text enclosed in quotation marks can be done in the following ways: ...
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