Google Publisher Tag (GPT) is a JavaScript library designed by Google to enable publishers to define ad slots on their web pages, request advertisements from Google Ad Manager, and display them to users. This script operates by communicating with Google's ad servers to fetch and render dynamic advertisements, integrating various ad formats and targeting options. Upon execution, it initializes the ad environment, manages ad slot configurations, and facilitates the loading of ads. It plays a critical role in website monetization strategies, allowing for the dynamic delivery of ads based on factors such as user demographics, browsing behavior, and page content, while also handling ad viewability tracking and user interaction measurement. The script actively manipulates the Document Object Model (DOM) to insert ad units and ensures the advertisements are presented efficiently and effectively.