CSS HTML Validator (previously named CSE HTML Validator) is an

HTML editor An HTML editor is a program for editing HTML, the markup of a web page. Although the HTML markup in a web page can be controlled with any text editor, specialized HTML editors can offer convenience and added functionality. For example, many HT ...

and CSS editor for

Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for ser ...

(and

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

when used with

Wine Wine is an alcoholic drink typically made from fermented grapes. Yeast consumes the sugar in the grapes and converts it to ethanol and carbon dioxide, releasing heat in the process. Different varieties of grapes and strains of yeasts are m ...

) that helps web developers create syntactically correct and

accessible Accessibility is the design of products, devices, services, vehicles, or environments so as to be usable by people with disabilities. The concept of accessible design and practice of accessible development ensures both "direct access" (i. ...

HTML The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaSc ...

XHTML Extensible HyperText Markup Language (XHTML) is part of the family of XML markup languages. It mirrors or extends versions of the widely used HyperText Markup Language (HTML), the language in which Web pages are formulated. While HTML, prior ...

, and CSS documents (including

HTML5 HTML5 is a markup language used for structuring and presenting content on the World Wide Web. It is the fifth and final major HTML version that is a World Wide Web Consortium (W3C) recommendation. The current specification is known as the HTML ...

and

CSS3 Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML (including XML dialects such as Scalable Vector Graphics, SVG, MathML or XHTML). CS ...

) by locating errors, potential problems, and common mistakes. It is also able to check links, suggest improvements, alert developers to deprecated, obsolete, or proprietary tags, attributes, and CSS properties, and find issues that can affect

search engine optimization Search engine optimization (SEO) is the process of improving the quality and quantity of website traffic to a website or a web page from search engines. SEO targets unpaid traffic (known as "natural" or " organic" results) rather than dire ...

. CSS HTML Validator is developed, marketed, and sold by AI Internet Solutions LLC located in

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

. The first version of CSS HTML Validator was released in 1997 for

Windows 95 Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturi ...

. The current version is 2022/v22.01 (as of July 22, 2022) and is for

Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was released to manufacturing on July 22, 2009, and became generally available on October 22, 2009. It is the successor to Windows Vista, released nearly ...

and above, including

Windows 11 Windows 11 is the latest major release of Microsoft's Windows NT operating system, released in October 2021. It is a free upgrade to its predecessor, Windows 10 (2015), and is available for any Windows 10 devices that meet the new Windows 11 ...

. There are four major editions of CSS HTML Validator — Enterprise, Pro/Professional, Home/Standard, and Lite. While the application is generally a commercial product (except for the Lite edition), a free version of the Home/Standard edition is available for personal/educational, non-commercial use.

Features

CSS HTML Validator includes an

validator A validator is a computer program used to check the validity or syntactical correctness of a fragment of code or document. The term is commonly used in the context of validating HTML,Tittel, Ed, and Mary C. Burmeister. HTML 4 for Dummies. --For d ...

for

, polyglot markup, CSS,

PHP PHP is a general-purpose scripting language geared toward web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementation is now produced by The PHP Group. ...

and

JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, of ...

(using

JSLint JSLint is a static code analysis tool used in software development for checking if JavaScript source code complies with coding rules. It is provided primarily as a browser-based web application accessible through the domain jslint.com, but ther ...

or JSHint), link checker (to find dead and broken links), spell checker, accessibility checker, and

(SEO) checker. An integrated web browser allows developers to browse the web while the pages are automatically validated. Because documents are checked locally and not uploaded over the Internet to a server in order to be checked, validations are performed relatively quickly, and security and privacy are increased. A custom scripting language called TNPL, included in the Pro and Enterprise editions, can be used to customize validations by adding, eliminating, or changing validator messages. TNPL can also be used to integrate customized validation checks to meet the unique requirements of an individual or entity. A Batch Wizard tool, included in the Pro and Enterprise editions, can check entire Web sites, parts of Web sites, or a list of local web documents. The Batch Wizard generates reports in HTML or XML format. The reports can be viewed using a standard web browser. The accessibility checker includes support for

Section 508 Amendment to the Rehabilitation Act of 1973 In 1998 the US Congress amended the Rehabilitation Act to require Federal agencies to make their electronic and information technology accessible to people with disabilities. Section 508 was enacted to eliminate barriers in information technolo ...

and

Web Content Accessibility Guidelines The Web Content Accessibility Guidelines (WCAG) are part of a series of web accessibility guidelines published by the Web Accessibility Initiative (WAI) of the World Wide Web Consortium (W3C), the main international standards organization for ...

(both WCAG 1.0 and WCAG 2.0/2.1). Using a version of

HTML Tidy HTML Tidy is a console application for correcting invalid HyperText Markup Language (HTML), detecting potential web accessibility errors, and for improving the layout and indent style of the resulting markup. It is also a cross-platform library ...

with HTML5 support and the Pretty Print & Fix Tool, CSS HTML Validator can automatically fix some common problems with

and

documents. However, some problems cannot be fixed (or fixed correctly) with automated tools and require manual review and repair.

Version history

Validation of polyglot markup was added in CSE HTML Validator v12, and mobile development support (for HTML and CSS) was added in CSE HTML Validator v14 and improved in v15. Version 15 added built-in syntax checking for JSON and HTML5 cache manifest files. Version 16 added JavaScript linting using JSHint, a static code analysis tool for checking JavaScript, but also continues to support

. Version 17 added support for the

Accelerated Mobile Pages Project AMP (originally an acronym for Accelerated Mobile Pages) is an open source HTML framework developed by the AMP Open Source Project. It was originally created by Google as a competitor to Facebook Instant Articles and Apple News. AMP is optimiz ...

, which is a type of HTML optimized for mobile web browsing, and support for live DOM validation using Google Chrome Version 18 renamed the software to CSS HTML Validator 2018 and includes updated HTML5 and CSS support. Version 18 also added a new "By Message" report in the Batch Wizard and dropped support for

Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...

and below. CSS HTML Validator 2019/v19 includes updated HTML and CSS support, adds WCAG 2.1 support, improves support when running under

Wine (software) Wine (formerly a recursive backronym for ''Wine Is Not an Emulator'', now just "Wine") is a free and open-source compatibility layer that aims to allow application software and computer games developed for Microsoft Windows to run on Unix-l ...

, and is a native 64-bit application (previously releases were 32-bit). CSS HTML Validator 2020/v20, first released in January 2020, includes HTML, CSS, accessibility, and other updates, including improved support for the

. Also, beginning with 2020/v20, the Standard edition was renamed to the Home edition. CSS HTML Validator 2021/v21, first released in January 2021, includes further HTML, CSS, accessibility, and other updates. CSS HTML Validator 2022/v22, first released in January 2022 and still the current release, includes more improvements and updates to keep the program up-to-date, a new rendering engine for the integrated web browser, and three new dark themes. Later updates to v22 added support for checking

JSON Lines JSON streaming comprises communications protocols to delimit JSON objects built upon lower-level stream-oriented protocols (such as TCP), that ensures individual JSON objects are recognized, when the server and clients use the same one (e.g. impl ...

and NDJSON documents. An online edition based on CSS HTML Validator Pro that can check documents via file upload, URL, or snippets (direct text input) was discontinued May 2017 in favor of the desktop version for Microsoft Windows.

Purpose of validation

The purpose of validation and computerized checking of HTML, XHTML, and CSS documents is to help make sure that the documents are syntactically correct and problem-free. Checked HTML, XHTML, and CSS documents are more likely to: * be more

for people with disabilities (such as blindness), as well as all users in general * render faster (user agents don't have to "figure out" and decipher bad syntax) * render as intended and with fewer problems on a variety of user agents, including

mobile device A mobile device (or handheld computer) is a computer small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physica ...

s * cause browsers and user agents to build a more consistent

Document Object Model The Document Object Model (DOM) is a cross-platform and language-independent interface that treats an XML or HTML document as a tree structure wherein each node is an object representing a part of the document. The DOM represents a document wi ...

, which is important for CSS and JavaScript * be forward-compatible with future versions of user agents and browsers ("future-proof") * be compatible with current and future HTML, XHTML, and CSS specifications * cause fewer problems for visitors and

web indexing Web indexing, or internet indexing, comprises methods for indexing the contents of a website or of the Internet as a whole. Individual websites or intranets may use a back-of-the-book index, while search engines usually use keywords and metadata t ...

* not contain dead, broken, or rotting links While automated checking tools are helpful for website development and maintenance, they cannot guarantee that a document will display as intended in all browsers. Developers should always test documents in a variety of browsers (including mobile browsers) to locate problems that cannot be detected with a computerized checking tool.

Differences from other HTML validators

* CSS HTML Validator is an offline desktop app for Microsoft Windows that does not require an Internet connection. The offline nature of CSS HTML Validator is in contrast to online and web-based services. * CSS HTML Validator primarily works offline (except for link checking when it must go online), which has speed and privacy benefits compared to web-based solutions and services like the

W3C Markup Validation Service The Markup Validation Service is a validator by the World Wide Web Consortium (W3C) that allows Internet users to check pre-HTML5 HTML and XHTML documents for well-formed markup against a document type definition. Markup validation is an impor ...

. However, the user must keep the software updated unlike web-based solutions which are typically kept updated by the solution provider. * CSS HTML Validator checks HTML/XHTML syntax, CSS, links, spelling, accessibility,

SEO Seo or SEO may refer to: * Search engine optimization, the process of improving the visibility of a website or a web page in search engines Organisations * SEO Economic Research, a scientific institute * Spanish Ornithological Society (''Socied ...

, and

with one pass, while DTD-based validators are more limited and cannot check

. * CSS HTML Validator includes a built-in scripting language (called TNPL) which allows for a high degree of customization via scripting and "user functions". This allows developers to add custom (specialized) validation checks and messages. * CSS HTML Validator includes a DTD-based validator which can optionally be used for checking DTD-based versions of HTML (versions prior to HTML5), however one of CSS HTML Validator's primary differences is that its custom validation engine can perform more checks on a document than a DTD-based validator can. This is because DTD-based validators are limited to checking only what can be specified in a Document Type Definition.

Integration

CSS HTML Validator integrates with other third-party software like those listed below. This allows validation using CSS HTML Validator from within the third-party program. *

EmEditor EmEditor is a lightweight extensible commercial text editor for Microsoft Windows. It was developed by Yutaka Emura of Emurasoft, Inc. It includes full Unicode support, 32-bit and 64-bit builds, syntax highlighting, find and replace with regular e ...

- includes a special Lite edition build of CSS HTML Validator 2019 for built-in checking of HTML and CSS * Blumentals Software - several Blumentals software products integrate with CSS HTML Validator * HTML-Kit * HomeSite * Microsys A1 Website Analyzer * PhpED * TextPad * TopStyleTopStyle Home Page
Retrieved 2013-01-22. - includes link checking support

References

External links

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{{HTML editors Web development