Nowadays JavaScript has three different keywords to declare a variable — var, let and, const. Each has its own properties and particularities. Let’s start by making a simple comparison table ...

JavaScript variables hold a wide variety of information and can be used with virtually any data type. Here's how to use variables to store numbers, text strings, objects, and more.

It's been a while since I worked on regexs in JavaScript, but generally the way you do this in most programming languages is to build the regex as a string and then pass it into the regex engine.