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Skip Navigation | Accessibility Validators | HTML Validators | Search Engine Marketing Validators | Accessibility Introduction | Accessibility References and Resources | Usability Introduction | Usability Resources | Search Engine Optimization References | InfoQuest!

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While most of the validators on this page have powerful fee-based versions, they all offer some form of free online validation of html syntax, accessibility, links, etc.

Accessibility Validators

Bobby -- Accessibility validator
This is the grandfather of accessibility validators from the Center for Applide Assistive Technology (CAST). The free version available from the website will validate single pages for either W3C or Section 508. The fee-based downloadable version will validate an entire website.

This is the accessibility validator developed by Pennsylvania's Initiative on Assistive Technology (PIAT). This tool identifies items on a Web page that should be examined for potential accessibility problems, and describes what the problem might be.

A-Prompt Toolkit
This is a downloadable tool that identifies potential accessibility problems and provides guided editing to correct the problems. The software is available through the joint efforts of the University of Toronto's Adaptive Technology Resource Centre (ATRC) and the TRACE Center at the University of Wisconsin.

Web Techniques: Considering the Color Blind
This validator tests your HTML on how it looks to people who are color-blind.

Visicheck Color Blindness Simulator
This simulator is available as a PhotoShop plug-in and in Java, as well as online. Visicheck Classic online checks images only, for all types of color blindness. VisicheckURL checks a single web page for red-green blindness (Deuteranope) only.

Public Lynx Access
One of the best ways to see how accessible your web pages are is in the Lynx text web browser. Lynx shows how your page reads in a linearized format, which is how most screen readers and other alternative browsers render HTML. The Public Lynx page offers several sites that allow guest access to a Lynx browser.

Accessibility Bookmarklets
These aren't really validator tools. Instead they are three small JavaScripts that easily enable you to configure Internet Explorer 5x+ browsers to view web pages in grayscale, to kill stylesheets, and to view the images on the page that don't have alt attributes. The bookmarklets are courtesy of 508Compliant.
Right click on each link and add to your bookmarks as a favorite.

HTML Validators

W3C Validator Service
The World Wide Web Consortium's free validator examines web pages against current and past HTML standards.

Web Design Group (WDG) HTML Validator
This validator uses a special SGML declaration with custom document-type definitions (DTDs), meaning that many custom DTDs, especially those built from the HTML 4.0 Transitional DTD, work correctly with the WDG HTML Validator but not other validators. You can validate on a page-by-page basis, using a batch mode, and even validate files on your own computer.

NetMechanic offers a limited free page validation service, as well as a fee-based website evaluation service that looks at whether the site meets HTML standards, browser compatibility, load time, and bad links. NetMechanic also has a separate, more extensive, browser compatibility service.

CSE HTML Validator
CSE provides downloadable validators that are highly rated by a number of sources, including TUCOWS and ZDNET. It checks HTML, XHTML, and WML syntax for Windows-based machines. The Lite version is free; the other versions are fee-based. The most recent Professional version has a free evaluation download, good for 50 pages.

Doctor HTML
The fee-based version of this validator provides analysis of an entire site. Individual pages can be tested free. The validator analyzes spelling, browser support, image syntax and analysis, font support, meta tags, form structure, table analysis, verifying links, document structure, load time, etc.

LinkScan's free online service, QuickCheck, allows you to check up to 10 web pages per hour and up to 50 per day with a limit of 200 Links per Document. It shows broken links, syntax errors, and good and bad source code. There are several versions of the fee-based version, which covers many more aspects of design and development.

Dr. Watson
This free service checks one page at a time for HTML syntax, regular and image links, generates word counts, spell checks non-HTML text, estimates download speeds, checks search engine compatibility and site link popularity.

Web Page Purifier
This site validates your web pages by various HTML standards, from HTML 4.0 Transitional to WebTV 1.1.
This was one of the first browser validator sites. It has a screen size test, a test that shows how your site looks to most search engines, a HTML validation test, a test that shows how your pages look to most viewers, a link test, and other tools.

Search Engine Validators

This service will tell you how many people have searched on whatever keywords or phrases you want. The service will tell you the number of searches on the phrase in the last 60 days, the estimated number of searches per 24 hour, period, the number of web pages containing the phrase (competition), and will identify the most effective key phrases. There is a limited trial version that uses Altavista as its test database. The fee-based version covers the major search engines, pay-per-click engines, and directories.

Overture Advertiser Center Tools
The pay-per-click service Overture provides several services to help people make the best decisions on choosing keywords and pricing bids.

Marketleap's Search Engine Marketing Tools
Search engine marketing company Marketleap offers a suite of free SEM tools. The Search Engine Saturation validator shows you the number of pages several top search engines have in their indexes for a given website domain, and compares that with up to five competitors. The Link Popularity analysis shows how many links a search engine has found for a website, compared with up to three competitors, and top sites within a specified industry. The Keyword Verification tool shows whether your website places in the top 30 results on a selected phrase in several search engines.

Bruce Clay's Check Redirect Codes Search engine optimization expert Bruce Clay offers a number of fee-based SEM tools on his website. This one is free. It performs a Socket TCP/IP Read for your site, a Request Read, and a Browser-type Get, that compares various header and source data to see if the site is the same and error free for each method. This is a way to see if the search engines see what people see, and highlight possible problems due to domain and server redirects.

Link popularity +
A very good link popularity tool that includes backwards links, allinurl, and contains link for Google. Also similar information for alltheweb, altavista, hotbot, msn and teoma. Can do mass reviews of up to 16 domains.

Google AdWords Suggestion Tool
Partial version of Google's suggestion tool. You can get expansions on suggested terms, but can only get estimated bids and click rates if you create an ad.

Top 10 Google Analysis
This service provides the top 10 sites for a keyword, along with the base URL. Gives the number of pages indexed by Google and Yahoo, backlinks for the page and domain, Google Page Rank, Yahoo Web Rank, AllInAnchor, body keyword density, and link keyword density. Requires a Google API.

Thumbspots Ranking
This service allows to compare the top 100 results for a term on two different search engines, or compare two different terms on the same search engine. You can highlight a particular site to see where the site ranks on both search engines. The output is visual, with lines connecting rankings on both search engines/terms. The text output includes overlapping links and unique links.

Poodle Predictor
This service shows how your site looks in search engine results. It shows the first 10 links on a page. The service also provides a Diagnostics view which shows how a search engine sees and reads your pages, a Source Code view, and a Meta/Header view.

Link Popularity Check
This is the WebPosition Link Popularity Check that searches Lycos, AllTheWeb, MSN, and Altavista to see how many pages on the Internet connect to a website.

Keyword Count
This site, by, helps you determine the keyword frequencies of top words on a web page, excluding HTML tags, and compare it with a competitor's page.

Link Popularity Service
PC Edge provides this free link popularity service that queries Google, Altavista and Hotbot.

Validator Directories

Yahoo! HTML Validation/Checkers
Yahoo!'s validator page highlights the most popular validators, and lists many others.

Table of Contents

Accessibility Introduction | Accessibility References and Resources | Usability Introduction | Usability Resources | Search Engine Optimization References | InfoQuest!

End Table of Contents

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Last updated: September 28, 2004
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