Year: 2022

This tutorial will demonstrate how to create a countdown timer in JavaScript, including a function you can copy and paste into your own code. The below code will break down creating a function which calculates the time until a certain future time, and how to run it repeatedly to affect a count down timer. Getting the time remaining until a certain date/time The below function will calculate the days, hours, minutes, and seconds to a target date: function timeToTarget(countdownString){ // Convert the string which specifies … Read more

This quick tutorial will show you how to find and replace text in JavaScript, with code examples. Replacing text in strings is something you will probably need to do quite often. JavaScript comes with the replace() method as part of it’s String objects to handle this functionality. JavaScript Strings JavaScript Strings are a type of variable used to store and manipulate a sequence of characters. There are also string primitives which represent only the characters and do not contain methods for manipulation, but JavaScript will implicitly convert between the two when required. The … Read more

The startsWith() String method in JavaScript will determine whether a string starts with a certain string or character. Here’s how it is used, with code examples. startsWith() Method JavaScript Syntax The startsWith() method can be called from any String variable. string.startsWith(SEARCH, START) Note that: string can be any string value or variable SEARCH should be the string which you want to check if string starts with START is OPTIONAL If specified, START will be used as the starting position when checking STRING The portion of the string before START will be ignored This can be useful if you want to check whether a … Read more

This article will show you how to get the current date, time, or both, in the JavaScript programming language. Code examples included. Date Objects in JavaScript Date objects represent a single point in time in JavaScript. They are created by initializing a new variable with a new Date object: var now = new Date(); By default, new Date objects are initialized to contain the date and time at the instant they were created, along with timezone details for the current device – thus representing the current … Read more

Promises are a feature of JavaScript which allow code to continue executing in the background, and perform an action with the result when it has completed. This article will show you how to use Promises. What is a ‘Promise’ in JavaScript? A Promise is an object in JavaScript which acts as a placeholder for the eventual result of an operation. A Promise is either: Pending while the operation completes Fulfilled when the operation is successful Rejected if the operation fails Promises allow for asynchronous code execution in JavaScript. … Read more

This tutorial will show you how to format numbers to a fixed number of decimal places in the JavaScript programming language. JavaScript Number Variables JavaScript variables have different types. The type of a variable defines what kinds of values it can hold, and what can be done with that value. Number typed variables hold numeric values and include a number of methods (built in functions) for performing numeric operations. Number variables are declared by simply assigning a numeric value to a variable, or using the Number … Read more

This article will show you how to check if a value is in an array in the JavaScript programming language. Code examples to check whether an array includes a value are provided. Arrays in JavaScript Arrays are a type of variable that hold an ordered list of values. Each value in an array has a position within the array, called the index. The index can be used to access each value in the array. Indexes are integer values, which start counting from 0 (zero) for the first … Read more