In this video, you’ll learn how to create and use the Custom JS variable in Tag Manager. We’ll show how to add this variable type, write simple JavaScript code with a return statement, and safely access browser objects like document or window. You’ll also learn how to reference other variables and use conditional checks to avoid errors. A practical example in debug mode shows how a Custom JS variable retrieves and returns dynamic values from a webpage. By the end, you’ll know how to use Custom JS variables to capture flexible, custom data that other variable types can’t provide.