Google Page Speed

Based on a Firefox/Chrome addon/extension, Page Speed Online from Google Labs is now available to use normally on any browser to analyze the content of a webpage. It then generates suggestions to make that page load faster by running a number of diagnostic tests against a page, analyzing its performance based on a number of conditions/rules that are known to speed up load time.

Principles such as resource caching, data upload, download size and client-server round-trip times are analyzed, and factors such as server configuration, JavaScript, CSS, image file properties and so on are examined. Page Speed gives a general score using a simple red/yellow/green grading scheme, and suggests specific techniques for correctly implementing fixes and optimisation.