AChecker : IDI Accessibility Checker: The W3C CSS Validation Service. World Wide Web Consortium (W3C) About REDbot. RED is a robot that checks HTTP resources to see how they'll behave, pointing out common problems and suggesting improvements. Although it is not a HTTP conformance tester, it can find a number of HTTP-related issues. using RED What does RED do? RED interacts with the resource at the provided URL to check for a large number of common HTTP problems, including: Invalid syntax in headers Ill-formed messages (e.g., bad chunking, incorrect content-length) Incorrect gzip encoding Missing headers Additionally, it will tell how well your resource supports a number of HTTP features, like: Caching Negotiation for compression Last-Modified and ETag validation Partial content See the source (available from the project page) for more details; RED's capabilities are added to all of the time.
What am I allowed to use this service for? Redbot.org may be used to check your resources as well as those owned by others. This service may not be framed, scraped or otherwise repurposed. RED and Privacy Yes. Caching Tutorial for Web Authors and Webmasters. For Web Authors and Webmasters This is an informational document. Although technical in nature, it attempts to make the concepts involved understandable and applicable in real-world situations. Because of this, some aspects of the material are simplified or omitted, for the sake of clarity. If you are interested in the minutia of the subject, please explore the References and Further Information at the end. What’s a Web Cache? Why do people use them? A Web cache sits between one or more Web servers (also known as origin servers) and a client or many clients, and watches requests come by, saving copies of the responses — like HTML pages, images and files (collectively known as representations) — for itself. There are two main reasons that Web caches are used: To reduce latency — Because the request is satisfied from the cache (which is closer to the client) instead of the origin server, it takes less time for it to get the representation and display it.
Kinds of Web Caches Browser Caches. WAVE Accessibility Validator. The W3C Markup Validation Service. Error Explanations for The W3C Markup Validation Service. IDI Web Accessibility Checker : Web Accessibility Checker.