# Introduction In this lab, we will be exploring a JavaScript function called `mask` that can be used to replace all but the last `num` characters of a given string with a specified mask character. We will learn how to use this function to create masked strings for sensitive data such as credit card numbers, phone numbers, or email addresses. By the end of this lab, you will have a solid understanding of how to use the `mask` function in your JavaScript projects.
Click the virtual machine below to start practicing