The Open Measurement SDK (OM SDK) is an industry-standard JavaScript library developed by the IAB Tech Lab, and omweb-v1.js represents Google's implementation for web environments. This script is loaded on web pages to enable independent third-party measurement of ad viewability and user interaction. Upon execution, the script initializes a framework that monitors the rendering and lifecycle of advertisements. It collects data points related to an ad's presence on screen, its size, the duration it is displayed, and user interactions such as clicks or scrolls. This data is then made available to authorized measurement partners through a standardized API, allowing them to verify ad impressions against industry viewability standards. Its behavior in the browser is non-intrusive from a user interaction perspective; it primarily observes and reports. The script focuses on creating a common language for viewability measurement, ensuring that various measurement vendors can retrieve consistent and reliable data regardless of the publisher or ad server. This standardization is crucial for advertisers to gain transparent insights into the performance and delivery quality of their digital ad campaigns.