Technique G134:Validating Web pages
Description
The objective of this technique is to avoid ambiguities in Web pages that often result from code that does not validate against formal specifications. Each technology's mechanism to specify the technology and technology version is used, and the Web page is validated against the formal specification of that technology. If a validator for that technology is available, the developer can use it.
Validation will usually eliminate ambiguities (and more) because an essential step in validation is to check for proper use of that technology's markup (in a markup language) or code (in other technologies). Validation does not necessarily check for full conformance with a specification but it is the best means for automatically checking content against its specification.
Examples
Example 1: Validating HTML
HTML pages include a document type declaration (sometimes referred to as !DOCTYPE
statement) and are valid according to the HTML version specified by the document
type declaration. The developer can use off-line or online validators (see Resources section) to check the validity of the HTML pages.
Example 2: Validating XML
SVG, SMIL and other XML-based documents reference a Document Type Definition (DTD) or other type of XML schema. The developer can use online or off-line validators (including validation tools built into editors) to check the validity of the XML documents.
Example 3: Batch validation with Ant
The xmlvalidate
task of Apache Ant can be used for batch validation of XML files. The following Apache
Ant target is a simple example for the validation of files with the extension .xml
in the directory dev\\Web
(relative to the Ant build file).
<target name="validate-xml"> <xmlvalidate lenient="no"> <fileset dir="dev/web" includes="*.xml" /> </xmlvalidate> </target>
Applicability
Any markup languages and many other technologies.
Tests
Procedure
For HTML, SGML-based and XML-based technologies:
- Load each page or document into a validating parser.
- Check that no validation errors are found.
For other technologies:
Follow the validation procedure defined for the technology in use, if any exists.
Expected Results
For HTML, SGML-based and XML-based technologies:
Check 2 is true.