Prince Varshney

Prince Varshney

22 Articles Published

Articles by Prince Varshney

Page 2 of 3

How to check the current runtime environment is a browser in JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 3K+ Views

A runtime environment is an environment where your code executes. It determines what global objects your code can access and affects its behavior. JavaScript can run in different environments like Node.js, Service Workers, or web browsers. Each browser comes with a JavaScript engine, so you can run JavaScript directly without additional software. Sometimes you need to detect which runtime environment your code is running in to ensure compatibility and use environment-specific features appropriately. Basic Browser Detection To check if the runtime environment is a browser, we can test for the presence of the global window object, which ...

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How to convert a value to a safe integer using JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 584 Views

An integer is known to be a safe integer if it can be exactly represented as an IEEE-754 double precision number. A safe integer is an integer in the range -(2^53 - 1) to (2^53 - 1). All these numbers are considered safe integers because they allow one-to-one mapping between mathematical integers and their representation in JavaScript. What is Number.isSafeInteger()? The Number.isSafeInteger() method determines whether a value is a safe integer. It returns true if the value is a safe integer, otherwise false. Syntax Number.isSafeInteger(testValue) Here testValue is the number to check if ...

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How to create dynamic values and objects in JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 9K+ Views

Dynamic values are values assigned to variables whose names are determined at runtime rather than being hard-coded. In JavaScript, we can use dynamic property names in objects, allowing us to create flexible object structures where property names can be changed without modifying the object definition directly. Dynamic objects are particularly useful when you need to create properties based on variables, user input, or computed values. The key technique involves using square brackets [ ] syntax to define property names dynamically. Syntax Following is the syntax to create dynamic values and objects: const key = 'PropertyName'; ...

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How to display a message when a given number is in the range using JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 921 Views

In this article, we will check whether a number lies between a range or not and display a message according to the output we get. This feature of JavaScript allows you to put a number validation while creating a form or any other document. Syntax Following is the syntax to check if number is in range and display the message − if (isNaN(number) || number < lower || number > upper) { document.getElementById("output").innerHTML = number + " is not in range"; } else { document.getElementById("output").innerHTML = number + " is ...

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How to pause and play a loop using event listeners in JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 1K+ Views

In this article, we'll learn how to pause and resume a JavaScript loop using event listeners and promises. This technique is useful for creating controllable animations, counters, or any iterative process that needs user interaction. An event listener attaches an event handler to an element, allowing us to respond to user interactions like button clicks. Syntax element.addEventListener(event, function, useCapture); Parameters event − The name of the event (e.g., "click") function − The function to execute when the event occurs useCapture ...

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How to return true if the bottom of the page is visible using JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 2K+ Views

In this tutorial, we will check if the bottom part of a page is visible or not to the user. We can do this functionality by using the height of the window and the height of the scrolled window. To write this code we need to understand three methods of JavaScript which are given as: scrollY − It is the read-only property of the window, and returns the pixels a document has scrolled vertically. window.scrollY scrollHeight − It is an HTML DOM element and a read-only property of the window. It returns the height of ...

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How to check if the constructor of an object is a JavaScript Object?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 1K+ Views

In this article, we will check whether the constructor of an object is a JavaScript Object. The constructor property of any JavaScript variable returns a reference to the Object constructor function that created the instance object. The value of this property is a reference to the function itself. All objects have the constructor property, and objects created without an explicit constructor function will have a constructor property that points to the fundamental Object constructor type for that object. To check whether the constructor of a provided value is an Object created by the object constructor function, we need ...

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How to detect a mobile device with JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 70K+ Views

In this tutorial, we are going to learn how can we detect a mobile device over which we are working using JavaScript. Approach 1: Using the navigator.userAgent Property To detect a mobile device with JavaScript we are going to use the window navigator object which contains all the information regarding a browser. The property which we will use to detect a mobile device will be the userAgent property which is used to return the user-agent header sent to the server by the browser. The value we receive from this property is the browser name, version, and platform i.e., ...

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How to define the number of nodes in a node list with JavaScript HTML DOM?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 677 Views

In this tutorial, we are going to learn how can we find the number of nodes present in a node list in JavaScript. To perform the specific operation, we need to use the HTML DOM which helps us to work with the object model of the webpage. Now let us first understand what a node is and what is a node list in HTML. Everything in an HTML document including element, text, attribute as well as the whole document is a node. Every small element present in an HTML document is part of the navigation tree of an HTML ...

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How to design a custom alert box using JavaScript?

Prince Varshney
Prince Varshney
Updated on 15-Mar-2026 12K+ Views

In this tutorial, we are going to create one custom alert box using JavaScript. The alert box signifies a box that appears with some message on it whenever you click a button and if we add some styling to the box and mould it according to our requirements then it will be a custom alert box. Approach to Design Custom Alert Box To create a custom alert box, we will use a jQuery library which is used to simplify the HTML DOM manipulation and it also provides us with better use of event handling and CSS animation with ...

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