w3c-markup-validator 1.3+dfsg-1 / usr / share / w3c-markup-validator / html / docs / users.html

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<div class="doc">

  <h2>User's guide for the W3C Markup Validator</h2>

  <h3 id="TableOfContents">Table of contents</h3>

  <div id="toc">
    <ul>
      <li><a href="#Quickstart">Quick Start</a></li>
      <li><a href="#Introduction">Introduction</a></li>
      <li><a href="#Calling">Calling/Linking to the Validator</a>
        <ul>
	  <li><a href="#API">Calling the validator's API</a></li>
        </ul>
      </li>
      <li><a href="#Options_Params">Validator's options and output formats</a>
        <ul>
	  <li><a href="#Options">Options and Parameters</a></li>
          <li><a href="#Output">Output Formats</a></li>
          <li><a href="api.html#http_headers">Using HTTP headers to know
              validation results</a></li>
	  <li><a href="#deprecated_options">Deprecated options</a></li>
        </ul>
      </li>
      <li><a href="#Interpret">Interpreting the results</a></li>
      <li><a href="#Installing">Installing the Markup Validator Locally</a></li>
    </ul>
  </div>

  <div id="Quickstart">
    <h3><a id="skip" name="skip"></a>Quick Start</h3>
    <p>
      Just type (or Cut&amp;Paste) the URL for the page you want to validate
      into the text field on the form and press the "Validate this page"
      button.
    </p>
    <p>
      If you have a local file you want to validate, choose the "File Upload"
      link from the navigation menu. Select the button labeled "Browse..." (or
      something like that, depending on your browser) and choose the file you
      want to upload in the usual manner for your OS.
    </p>
    <p>
      Alternatively, you can also copy and paste the <em>complete</em> markup
      (including a <a href="help.html#faq-doctype">DOCTYPE declaration</a>) for
      a document in the "direct input" box.
    </p>
  </div>

  <div id="Introduction" class="stb">
    <h3>Introduction</h3>
    <p>
      The W3C Markup Validation Service is a web gateway to SGML and XML parsers,
      and various other specialized validation services. The underlying
      implementations will take your document and compare it to a set of
      objective syntax rules for the submitted document.  For example for HTML
      documents this set of rules is called a "DTD", a Document Type Definition.
      This way you can be sure your HTML is really valid and not just that it
      conforms to some random programmer's idea of "nice" HTML. Note that valid
      HTML does not guarantee that your pages will work OK in all browsers.
      Most of them are severely broken and you may need to find alternate ways
      of achieving your goal.
    </p>
    <p>
      When you send an URL to the W3C Markup Validation Service, it will fetch
      that URL and feed it to the underlying parsers. If you upload a file it'll
      get fed directly into the parsers. We then take the output produced by the
      parsers and format it nicely as HTML and send it back to your web browser.
    </p>
    <p>
      The W3C Markup Validation Service is not generating the error messages -
      they are all generated by the underlying parsers - but it is appending
      short explanations and suggested fixes for each error. We provide a
      <a href="../feedback.html#errormsg">feedback channel</a> for users to
      suggest better explanations and more accurate solutions.
    </p>
  </div>

  <div id="Calling" class="stb">
    <h3>Calling/Linking to the Validator</h3>
    <p>
      You can link directly to the Validator home page, or you can call the
      Validator CGI program. The home page is
      &lt;<a href="http://validator.w3.org/">http://validator.w3.org/</a>&gt;
      at the moment (and for the foreseeable future) and the CGI program can be
      reached at &lt;http://validator.w3.org/check&gt;.
    </p>
    <p>
      If you call the CGI program with the "uri=referer" query string parameter
      (i.e. &lt;<a href="http://validator.w3.org/check?uri=referer">http://validator.w3.org/check?uri=referer</a>&gt;)
      it will fetch the referring document and validate that. This means that
      if you embed a link to that URL in your pages, following on that link
      will send you the validation results for that page.
    </p>
    <p>
      You can also link to the validation results for a specific page. You do
      this by giving "check" an "uri" parameter pointing at the page you want
      to validate. For example
      &lt;<a href="http://validator.w3.org/check?uri=http%3A%2F%2Fwww.example.com%2F">http://validator.w3.org/check?uri=http%3A%2F%2Fwww.example.com%2F</a>&gt;
      will validate the www.example.com home page.
    </p>
    <p>
      The various options are listed below in the section
      "<a href="#Options">Options and Parameters</a>" in parenthesis after the
      long name. To add options to your links directly, append the options
      separated by a semicolon. For example
      &lt;<a href="http://validator.w3.org/check?uri=http%3A%2F%2Fwww.example.com%2F;ss=1;outline=1">http://validator.w3.org/check?uri=http%3A%2F%2Fwww.example.com%2F;ss=1;outline=1</a>&gt;
      will validate the example.com home page with "Show Source", and "Outline"
      on, but "Verbose" off.
    </p>
    <p>
      All parameter values should be encoded in the UTF-8 character encoding
      (before URI escaping them).
    </p>
    <p>
      You may also see these separated by ampersands, but this usage is
      deprecated and support may be removed at some time in the future.
    </p>

    <h4 id="API">Calling the validator's API</h4>
    <p>
      The Validator can also be called by programs through its
      <a href="api.html">API</a>. See full documentation for details.
    </p>
  </div>

  <div id="Options_Params" class="stb">
    <h3>Options and output formats</h3>
    <h4 id="Options">Options and Parameters</h4>
    <p>
      In addition to the text field where you enter an URL -- or the file
      selection field if you are uploading files -- there are a few checkboxes
      that alter the behaviour of the validator.</p>
    <p>
      These options are:
    </p>

    <dl>
      <dt><a id="option-charset" name="option-charset"></a>Encoding</dt>
      <dd>
        <p>This allows you to <strong>override</strong> the character encoding
	  information about your document. You may use this option for test
	  purposes, but you will eventually have to serve your document with
          the correct character encoding, or the validator will
          <a href="help#faq-charset">complain</a> about it and you document
          will not be valid.</p>
      </dd>
      <dt><a id="option-fbc" name="option-fbc"></a>Use Fallback instead of
        Override (Encoding) (<code>fbc</code>)</dt>
      <dd>
        <p>Uses the <a href="#option-charset">character encoding override</a>
          mechanism described above, but only does it as a fall back mechanism
          if the actual document is not served with character encoding
          information. Think of this as a gentler override mechanism.
        </p>
      </dd>
      <dt><a id="option-doctype" name="option-doctype"></a>Document Type
        (Doctype) (<code>doctype</code>)</dt>
      <dd>
        <p>
          This allows you to <strong>override</strong> the DOCTYPE declaration
          for your document. You may use this option for test purposes, but you
          will eventually have to serve your document with the correct DOCTYPE
          declaration, or the validator will
          <a href="help#faq-doctype">complain</a> about it and you document
          will not be valid.
        </p>
      </dd>
      <dt><a id="option-fbd" name="option-fbd"></a>Use Fallback instead of
        Override (Type) (<code>fbd</code>)</dt>
      <dd>
        <p>
          Uses the <a href="#option-doctype">Doctype override</a> mechanism
          described above, but only does it as a fall back mechanism if the
          actual document does not have a Doctype declaration. Think of this as
          a gentler override mechanism.
        </p>
      </dd>

      <dt><a id="option-ss" name="option-ss"></a>Show source input
        (<code>ss</code>)</dt>
      <dd>
        <p>
          Displays the HTML source of the document you validated and links
          error messages directly to lines in this output. Makes it easy to see
          what's wrong.
        </p>
      </dd>
      <dt><a id="option-outline" name="option-outline"></a>Show an outline of
        this document (<code>outline</code>)</dt>
      <dd>
        <p>
          Will generate an outline of your document from the H1 - H6 elements.
          For a properly formed document, this will be a nicely nested tree
          structure. The visualization of your document's structure makes it
          easier to see where you've skipped a heading.
        </p>
        <p>
          If you want to examine the semantic structure of your documents,
          beyond the outline, try the
          <a href="http://www.w3.org/2003/12/semantic-extractor.html">Semantic
            data extractor</a>.
        </p>
      </dd>
      <dt><a id="option-no200" name="option-no200"></a>Validate error pages
        (<code>No200</code>)</dt>
      <dd>
        <p>
          The Markup Validator will usually tell you if the page you tried to
          validate could not be retrieved (for example, if the server gave a
          "404 not found" message. In some circumstances you may want to be
          able to validate the error page sent by the server. This is the
          option to use then.
        </p>
      </dd>
      <dt><a id="option-verbose" name="option-verbose"></a>Verbose Output
        (<code>verbose</code>)</dt>
      <dd>
        <p>
          This option triggers verbose output. Verbose output adds more
          explanations and suggestions to the validation results, and gives
          more information on the resource validated. This makes it a useful
          option if you prefer to be given as much help as possible; if you
          prefer more concise reports, leave this option unset.
        </p>
      </dd>
      <dt id="option-accept">For Content-Negotiated resources, set a specific
        <code>Accept</code> Header (<code>accept</code>)</dt>
      <dd>
        <p>
          This option (<em>experimental, as of 0.8.2</em>) is useful if your
          Web server is set up to use format negotiation, serving different
          content based on the preferred/accepted media types of the user
          agent. The validator can then emulate different HTTP
          <code>Accept</code> behaviors.
        </p>
        <p>
          For example, append
          "<code>accept=application%2Fxhtml%2Bxml%2C*</code>" and the validator
          will send the HTTP Header
          "<code>Accept: application/xhtml+xml,*</code>".
        </p>
      </dd>
      <dt id="option-accept-language">For Content-Negotiated resources, set a
        specific <code>Accept-Language</code> Header (<code>accept-language</code>)</dt>
      <dd>
        <p>
          This option (<em>experimental, as of 0.8.2</em>) is useful if your
          Web server is set up to use language negotiation, serving content in
          different languages based on the preferred/accepted language setup of
          the user agent. The validator can then emulate different HTTP
          <code>Accept-Language</code> behaviors.
        </p>
        <p>
          For example, append "<code>accept-language=ja%2Cfr</code>" and the
          validator will send the HTTP Header
          "<code>Accept-Language: ja,fr</code>".
        </p>
      </dd>
      <dt id="option-accept-charset">Set a specific <code>Accept-Charset</code>
        Header (<code>accept-charset</code>)</dt>
      <dd>
        <p>
          This option (<em>experimental, as of 0.8.3</em>) makes the validator
          send an <code>Accept-Charset</code> HTTP header, specifying the
          character encodings which it will accept from server. This option is
          mainly used to interface the Markup Validator for
          <a href="http://www.w3.org/TR/mobileOK-basic10-tests/#http_request">Mobile
            Web Best Practices</a> checking.</p>
      </dd>
      <dt id="option-user-agent">Set a specific <code>User-Agent</code> Header
        (<code>user-agent</code>)</dt>
      <dd>
        <p>
          This option (<em>experimental, as of 0.8.3</em>) makes the validator
          send a custom <code>User-Agent</code> HTTP header instead of the
          usual <code>W3C_Validator/xx.xxxx</code>. If the value of this
          parameter is <code>mobileok</code>, the validator will output a
          <code>User-Agent</code> string as defined by the
          <a href="http://www.w3.org/TR/mobileOK-basic10-tests/#http_request">Mobile
            Web Best Practices</a> spec.</p>
      </dd>
    </dl>

    <h4 id="Output">Output Options</h4>
    <p>
      In addition to the HTML output intended for human consumption in a
      browser, the Validator has some experimental features to generate machine
      parseable output in a few different forms. To enable these output
      options, append "<code>;output=&lt;option&gt;</code>" to the URL of the
      validation results (an interface for these options will be provided when
      they exit the beta stage).
    </p>
    <dl>
      <dt id="output-soap12">Web Service API (<code>output=soap12</code>)</dt>
      <dd>
        Using the SOAP1.2 language over HTTP, this defines a web service with
        an output similar to the API for the W3C CSS validator and Feed
        Validator. The <a href="api">Full documentation</a> for this API is
        available. This API is <em>still under development</em>, and subject to
        change.
      </dd>
      <dt id="output-json">JSON (<code>output=json</code>)</dt>
      <dd>
        Produces output using a JSON (JavaScript Object Notation) formatting
        equivalent to the
        <a href="http://wiki.whatwg.org/wiki/Validator.nu_JSON_Output">JSON
          output for validator.nu</a>.
      </dd>
      <dt id="output-earl">EARL/RDF (<code>output=earl</code>)</dt>
      <dd>
        Produces output in the
        <a href="http://www.w3.org/TR/EARL10-Schema/">EARL 1.0 RDF</a> syntax.
        <em>This output may change or be removed in the future</em>.
      </dd>
      <dt id="output-n3">Notation3 (<code>output=n3</code>)</dt>
      <dd>
        Produces output in the Notation3 RDF syntax.
        <em>This output is currently outdated and may change or be removed
          in the future</em>.
      </dd>
    </dl>

    <h4 id="deprecated_options">Deprecated options</h4>
    <p>
      A number of options once available  have been deprecated and are not
      available any more. These include the <em>Show parse tree</em> and
      <em>exclude attributes from the parse tree</em>, as well as
      <em>Show ESIS</em> and <em>Show raw errors</em> options, and the
      <code>xml</code> output option.
    </p>
  </div>


  <div id="Interpret" class="stb">
    <h3>Interpreting the results</h3>
    <p>
      In spite of our efforts,  interpreting the Markup Validator's error
      messages isn't quite what you'd call easy. The error messages are
      generated in the context of a full SGML environment which demands a
      somewhat higher level of technical detail than your average HTML
      document. We have set up a page listing <a href="errors.html">errors and
        their explanations</a>, which should help you find out what meaning
      lies behind the cryptic messages, and fix your markup.
    </p>
    <p>
      We're working on ways to make the error messages more friendly, but for
      now, if the <a href="errors.html">errors explanation page</a> doesn't
      work for you, or if you wish to suggest a better explanation, our
      <a href="../feedback.html#errormsg">feedback page</a> will help you send
      your ideas to our public mailing list. This will have the added benefit
      of letting us know which error messages are causing the most trouble so
      we can fix those first. Please be as specific as possible and include the
      <em>exact</em> error message and, preferably, a URL we can validate to
      see for ourselves.
    </p>
  </div>

  <div id="Installing" class="stb">
    <h3>Installing a local Validator</h3>
    <p>
      You can download the Validator to run on your own system. For Web design
      departments or agencies it can be a very good idea, saving time and
      allowing you to not send documents under work or confidential pages over
      the wire, but it is a complex operation, and is not recommended for
      average users, for which the free online service at W3C should suffice.
    </p>
    <p>
      We have created a simple <a href="install.html">Installation manual</a>,
      which, along with the <a href="devel.html">Developer's information</a>,
      should help you install a local instance of the Markup Validator in your
      own network easily.
    </p>
  </div>
</div>

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