BaseScripts — Practical Code. Powerful Foundations
Build Faster with Scripts You Can Learn From and Use
Laurence Svekis 
What are the differences between var, let, and const? In JavaScript, var, let, and const are used to declare variables, but they have different scoping rules and behaviors. Here’s a detailed explanation of the differences between them: var: Variables declared with var are function-scoped or globally-scoped. They are hoisted to the top of their scope, … Read more
In JavaScript, null and undefined are both special values that represent the absence of a value. However, they have different use cases and behaviors. Here’s a detailed explanation of the difference between null and undefined: undefined: undefined is a primitive value in JavaScript. It is used to indicate the absence of an assigned value to … Read more
What are the different data types in JavaScript? JavaScript has several built-in data types that are used to represent different kinds of values. Here are the different data types in JavaScript: Number: Represents numeric values. It can be an integer or a floating-point number. For example: var age = 25; var temperature = 98.6; String: … Read more
In JavaScript, you can make an HTTP request using the XMLHttpRequest object or the newer fetch() function. Here’s an example of how to make an HTTP GET request using both methods: Using XMLHttpRequest: var xhr = new XMLHttpRequest(); xhr.open(“GET”, “https://api.example.com/data”, true); xhr.onreadystatechange = function() { if (xhr.readyState === 4 && xhr.status === 200) { var … Read more
The given code consists of two functions: FACTORIALVAL and test1. Let’s break down each function and its purpose: FACTORIALVAL(val): This function calculates the factorial value of a given number val. It first checks if the val is equal to 0. If it is, the function immediately returns 1. This is the base case of the … Read more
Google Sheet Formulas Formula to calculate the average of the values in a given rangeConcatenate two strings and capitalize the first letterCalculate the factorial of a given numberCount the number of occurrences of a given value in a rangeCalculate the distance between two sets of latitude and longitude coordinatesCheck if a given string is a … Read more
The code defines a function called DISTANCE_BETWEEN that calculates the distance between two geographical coordinates on the Earth’s surface using the Haversine formula. Here’s a step-by-step breakdown of the code: Define a constant earthRadius with a value of 6371, representing the Earth’s radius in kilometers. Calculate the difference in latitude (dLat) and longitude (dLon) between … Read more
In JavaScript, when an HTML element has an id attribute defined, it automatically becomes available as a global variable in the DOM (Document Object Model). This means you can directly access that element using its id as a variable without the need for any explicit lookups or queries. For example, if you have an HTML … Read more
AJAX examples The provided code handles the submission of a form and makes an asynchronous request to a specified URL using different AJAX techniques (jQuery, Axios, Fetch, and plain JavaScript). It also displays the response received from the server. document.addEventListener(“DOMContentLoaded”, function(event) { document.querySelector(‘input[name=”sender”]’).addEventListener(‘click’, makeRequest); }); var method = document.getElementById(‘method’); method.addEventListener(‘change’, function() { var myForm = … Read more
You can use the FormData API in JavaScript. Here’s an example of how you can serialize form data: function serializeFormData(form) { var formData = new FormData(form); var serializedData = {}; for (var [name, value] of formData) { if (serializedData[name]) { if (!Array.isArray(serializedData[name])) { serializedData[name] = [serializedData[name]]; } serializedData[name].push(value); } else { serializedData[name] = value; } … Read more