The purpose of this tutorial is to introduce you to regular expressions and demonstrate how they work. A regular expression, or regex, is a sequence of characters that illustrate or define a search pattern. They are used to find, match, replace, or validate input in strings. Regular expressions are used in many programming languages, my tutorial will focus on their use in JavaScript.
The following is the regular expression for matching a hexadecimal color value that we will be examining in this tutorial:
/^#?([a-f0-9]{6}|[a-f0-9]{3})$/