Free HTML / CSS / Link Validators
Checks for HTML / CSS errors, browser compatibility, broken links, standards compliance
Free HTML / CSS / Link Validation - Check for Errors, Standards Compliance, Broken Links
In a nutshell: this page lists HTML validators (which check HTML code for standards compliance and errors), CSS validators (which check Cascading Style Sheets for errors and standards compliance), browser compatibility checkers (checks your page to see if it is compatible with various browsers), broken link (or dead links) checkers, accessibility checking (check if your web page is accessible to people with disabilities), etc. Note that this page lists both free online services as well as free offline tools (programs). It does not list commercial HTML or CSS validation tools such as the CSE HTML Validator (other than to mention it in passing, in this sentence).
If you have arrived here looking for a way to create your own website, you may find it more helpful to start with How to Create / Make a Website: The Beginner's A-Z Guide instead. The tutorial takes you through all the steps needed to start your own site in an easy-to-understand manner.
Finally, besides using the validators, if you want to check your web page for accessibility, you might also be interested in the Free Screen Readers: Text to Speech Conversion page. There's nothing like using the very tools that are used by the blind to experience what they face when they arrive at your website. My primer on accessibility, How to Improve the Accessibility of Your Website may be useful too.
Free HTML Validators, XHTML Validators, Browser Compatibility Checkers
- W3C HTML Validation Service
You can use the W3 Consortium's HTML validator to check your web documents either by giving it your web page's URL or uploading your document directly to the validator. Many people consider it the authoritative source for checking your web pages for standards compliance (since the W3 Consortium is responsible for the various HTML/CSS standards). Source code for the validator is also available.
- HTML Tidy (HTML Validator)
HTML Tidy is an HTML validator that is able to check your web pages and correct (ie, repair / fix) bad HTML code, or point out areas that you need to change in order to make your site accessible to people with disabilities. The program is free, runs on a variety of systems including Windows, Mac OS X, Linux, etc. This is an open source program. Note: the newest version, located at the above address, did not have any executables/binaries (programs that are ready-to-run) available at the time I wrote this entry, since the programmers were still testing it. The executables may already be downloadable by the time you read this, but if they are not, you can still find older versions at the original HTML Tidy Library Project page with binaries for Windows, Mac OS, Atari, Amiga, BeOS, AIX, Linux, UnixWare, HP-UX, MSDOS, Solaris, OS/2, FreeBSD, RISC OS, MiNT (Atari) OS, etc. The old version does not have support for HTML5.
- Tidy Online
This is an online version of the HTML Tidy validator that you can use to clean up your web pages if you're too lazy to download your own copy. (To get your own copy, see elsewhere on this page - listed under "HTML Tidy".)
- Web Page Purifier
The Web Page Purifier allows you to check your HTML pages for compliance ("purity") with various HTML standards (eg HTML 4.0 Transitional, HTML 4.0 Strict, WebTV 1.1, HTML 3.2, etc). There's a form where you can enter the URL of the page to check, or you can also download the Perl CGI source code.
- Web Page Backward Compatibility Viewer
If you need to check your web pages to see if they are compatible with browsers that lack certain features, this page checker might be useful. You actually have to specify which features you do not want on a page, like tables, images, etc. It is probably not as useful as the title of the site sounds, since if you knew which features you needed to avoid, you would not put them in a page in the first place. (It would be better if there were simple options where you could simply select the browser versions you want to check compatibility with, instead of having to specify features.)
Free Web Page Accessibility Checkers
- ATRC Web Accessibility Checker
The ATRC Web Accessibility Checker is a free online service that checks your website for accessibility issues. You can use it by either supplying it with your website's address or by uploading the page you want to test from your browser.
- WAVE Accessibility Tool
- Cynthia Says Portal
Cynthia checks your site against the US Section 508 standards and the Web Content Acessibility Guidelines (WCAG). It only allows you to test one page at a time.
Free Cascading Style Sheets (CSS) Validators
- W3C CSS Validation Service
This is the W3 Consortium's CSS validator for validating Cascading Style Sheets. You can either download it and use it on your own machine, upload your cascading style sheet (CSS) to their online service, or supply your URL for their spider to visit your site. The W3 Consortium is responsible for the various CSS and HTML standards.
- CSSCheck: Cascading Style Sheets Lint
This is a validator for Cascading Style Sheets (CSS) that also looks into a few browser compatibility issues with your style sheet.
Free Broken Links Validators
- W3C Link Checker
Worried about broken links in your web documents? This online validator from the W3 Consortium is able to recursively check your document for dead links. You simply enter a URL in the form provided, and it will visit your site and check the links.
- Xenu Link Sleuth: Find Broken Links
Xenu is a utility for Windows that checks your web site for broken links. It can work both with a "live" website as well as on a copy of your web site residing on your own hard disk. It's a favourite of many webmasters for checking broken links on their site.
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