A browser-based tool is provided that loads a Webpage, accesses the document object model (DOM) of the page, collects information about the page structure and parses the page, determines through the use of heuristics such factors as how much text is found on the page and the like, produces statistical breakdown of the page, and calculates a score based on performance of the page. Key to the operation of the invention is the ability to observe operation of the Webpage as it actually loads in real time, scoring the page for several of various performance factors, and producing a combined score for the various factors.