Total Load: Onload Time, Fully Loaded Time, Speed Index

The question "when is the website done loading?" seems like it should have a simple answer. Ultimately though, webpages are never truly done loading. As visitors interact with a page, more resources may need to be loaded, more code may need to be executed, or the browser may need to repaint portions of the page to display new content. Yet, there are points at which the page has completed key aspects of the initial load. At these points, visitors can begin using and interacting with different parts of the webpage.