getElementsByTagName select element weirdness

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  • Andy Chambers
    #1

    getElementsByTagName select element weirdness

    Hi,

    On both Opera and Firefox, getElementsByTa gName doesn't find anything
    apart from <optionelemen ts inside a select element. Why is this?
    Here's a page that demonstrates this behaviour. I'd have thought the
    correct behaviour would be to show "count: 1" but instead, you get
    "count: 2".

    Is this because only <option>s <select>s?

    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    <title>
    </title>
    <script type='text/javascript'>
    window.onload = function() {
    var elems = document.getEle mentsByTagName( "xref");
    alert("count: " + elems.length);
    };
    </script>
    <style type='text/css'></style>
    </head>
    <body>
    <div id='banner'>
    <h1>
    </h1>
    </div>
    <div id='content'>
    <select>
    <xref ref="1"/>
    </select>
    </div>
    </body>
    </html>


    Cheers,
    Andy
    Tags: None
    • Thomas 'PointedEars' Lahn
      #2
      Re: getElementsByTa gName select element weirdness

      Andy Chambers wrote:
      On both Opera and Firefox, getElementsByTa gName doesn't find anything
      apart from <optionelemen ts inside a select element. Why is this?
      You are trying to use extended XHTML, and your markup is not Valid.[1] The
      "Extensible " in XHTML does _not_ mean "anything goes"; if you want to extend
      XHTML, you need to declare a namespace for all non-XHTML elements and
      attributes and a DTD or a Schema that declares these elements and
      attributes. And of course you must comply with the XHTML DTD (that you
      missed to declare here), which says in your case (assuming XHTML 1.0
      Transitional or Strict):

      | <!ELEMENT select (optgroup|optio n)+ <!-- option selector -->

      Meaning that an XHTML `select' element must contain at least one of
      `optgroup' or `option' elements.
      [...]
      Is this because only <option>s <select>s?
      Parse error.
      <html xmlns="http://www.w3.org/1999/xhtml">
      This declares the XHTML namespace as the default namespace.
      [...]
      var elems = document.getEle mentsByTagName( "xref");
      [...]
      <body>
      [...]
      <select>
      <xref ref="1"/>
      </select>
      [...]
      </body>
      </html>
      Therefore, you need to use namespace-based accessor methods in an XHTML
      document. Suppose your `xref' element was declared in
      <http://achambers.me.uk/dtds/ac.dtdlike this:

      ...
      <!ELEMENT select (optgroup|optio n|xref)+>
      ...
      <!ELEMENT xref EMPTY>
      <!ATTLIST xref
      ref CDATA #REQUIRED
      >
      ...

      And used like this:

      <DOCTYPE html PUBLIC "-//AChambers//DTD XHTML 1.0 plus ACMarkup//EN"
      "http://achambers.me.uk/dtds/xhtml1-acmarkup.dtd">
      <html xmlns="http://www.w3.org/1999/xhtml">
      xmlns:ac="http://achambers.me.uk/acmarkup"
      xml:lang="en">
      ...
      <body>
      ...
      <ac:xref ref="1"/>
      ...
      </body>
      </html>

      You would access it like this:

      var elem = document.getEle mentsByTagNameN S(
      "http://achambers.me.uk/acmarkup", "xref")[0];


      PointedEars
      ___________
      [1] <http://validator.w3.or g/>
      --
      Prototype.js was written by people who don't know javascript for people
      who don't know javascript. People who don't know javascript are not
      the best source of advice on designing systems that use javascript.
      -- Richard Cornford, cljs, <f806at$ail$1$8 300dec7@news.de mon.co.uk>

        Comment

        • Thomas 'PointedEars' Lahn
          #3
          Re: getElementsByTa gName select element weirdness

          Thomas 'PointedEars' Lahn wrote:
          [...] Suppose your `xref' element was declared in
          <http://achambers.me.uk/dtds/ac.dtdlike this:
          >
          [...]
          And used like this:
          >
          <DOCTYPE html PUBLIC "-//AChambers//DTD XHTML 1.0 plus ACMarkup//EN"
          "http://achambers.me.uk/dtds/xhtml1-acmarkup.dtd">
          [...]
          Those two URIs must be the same, of course.


          PointedEars
          --
          realism: HTML 4.01 Strict
          evangelism: XHTML 1.0 Strict
          madness: XHTML 1.1 as application/xhtml+xml
          -- Bjoern Hoehrmann

            Comment

            • Andy Chambers
              #4
              Re: getElementsByTa gName select element weirdness

              Thomas 'PointedEars' Lahn wrote:
              <DOCTYPE html PUBLIC "-//AChambers//DTD XHTML 1.0 plus ACMarkup//EN"
              "http://achambers.me.uk/dtds/xhtml1-acmarkup.dtd">
              [...]
              >
              Those two URIs must be the same, of course.
              So does the browser actually lookup the DTD and validate the document
              before loading it? Does it have to be a DTD or could it be something
              else that defines your allowable elements (e.g. relaxng or w3c
              schema).

              Is it possible to extend plain old html in this way or is that the
              whole point of xhtml?

              Cheers,
              Andy

                Comment

                • Martin Honnen
                  #5
                  Re: getElementsByTa gName select element weirdness

                  Andy Chambers wrote:
                  On both Opera and Firefox, getElementsByTa gName doesn't find anything
                  apart from <optionelemen ts inside a select element. Why is this?
                  Here's a page that demonstrates this behaviour. I'd have thought the
                  correct behaviour would be to show "count: 1" but instead, you get
                  "count: 2".
                  Do you serve the document as text/html or as application/xhtml+xml or
                  application/xml or text/xml?
                  Why do you say "doesn't find anything" if count is 2?



                  --

                  Martin Honnen
                  Attention Required! | Cloudflare
                  http://JavaScript.FAQTs.com/

                    Comment

                    • RobG
                      #6
                      Re: getElementsByTa gName select element weirdness

                      Andy Chambers wrote:
                      Thomas 'PointedEars' Lahn wrote:
                      >
                      >><DOCTYPE html PUBLIC "-//AChambers//DTD XHTML 1.0 plus ACMarkup//EN"
                      >> "http://achambers.me.uk/dtds/xhtml1-acmarkup.dtd">
                      >>[...]
                      >Those two URIs must be the same, of course.
                      >
                      So does the browser actually lookup the DTD and validate the document
                      before loading it? Does it have to be a DTD or could it be something
                      else that defines your allowable elements (e.g. relaxng or w3c
                      schema).
                      >
                      Is it possible to extend plain old html in this way or is that the
                      whole point of xhtml?

                      That is getting OT for this news group, though some here likely know the
                      answer. Try:

                      news:comp.infos ystems.www.authoring.html


                      But beware, some there have a passionate dislike of XHTML (which is not
                      a hint to not post, only to be tolerant of some replies you'll get). :-)


                      --
                      Rob

                        Comment

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