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Es handelt sich dabei um eine Fehlermeldung des Feed-Validators, die eventuell noch ins Deutsche übersetzt werden muss. Wenn du kannst, hilf mit!
Es handelt sich dabei um eine Fehlermeldung des Feed-Validators, die eventuell noch ins Deutsche übersetzt werden muss. Wenn du kannst, hilf mit!
Status dieser Fehlermeldung: Noch nicht übersetzt
Meldung
<p>Undefined named entity: <code>foo</code></p>
Erklärung
<p>Your feed is not <a href="http://www.w3.org/TR/REC-xml/#sec-well-formed">well formed</a> according to the <a href="http://www.w3.org/TR/REC-xml">XML specification</a>. It makes use of a named entity other than one of the ones <a href="http://www.w3.org/TR/REC-xml/#sec-predefined-ent">predefined</a> in the XML specification: <code>&lt;</code> for <code><</code>, <code>&amp;</code> for <code>&</code>, <code>&gt;</code> for <code>></code>, <code>'</code> for <code>&apos;</code>, and <code>&quot;</code> for <code>".</code></p>
Lösung
<p>It is possible to create a <a href="http://www.w3.org/TR/REC-xml/#dt-doctype">DTD</a> which declares additional <a href="http://www.w3.org/TR/REC-xml/#sec-entity-decl">entities</a>, reference this DTD in a <a href="http://www.w3.org/TR/REC-xml/#NT-doctypedecl">DOCTYPE declaration</a>, and then make use of such entities. XHTML defines a <a href="http://www.w3.org/TR/xhtml1/#normative">set of such doctypes</a> which defines additional <a href="http://www.w3.org/TR/xhtml1/#h-A2">entities</a>. Support for the HTML and XHTML doctypes in now widespread — in browsers. While the Feed Validator will validate feeds which make use of DTDs specifically defined for use with Atom or RSS, the support for such advanced — and optional — XML features is not widespread in feed readers. As such, this approach is <b>not recommended</b>.</p>
<p>One solution that <b>is</b> widely supported is to replace the use of named entity references with their <a href="http://www.w3.org/TR/REC-xml/#sec-entity-decl">numerical equivalents</a>. For example, use <code>&#160</code> or <code>&#xa0;</code> instead of <code>&nbsp;</code>. A complete list of XHTML characters and their numeric equivalents can be found <a href="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_Latin-1_characters">here</a>. Many programming languages have libraries that can assist with this task.</p>
<p>Another approach it to make use of entity-encoded HTML. For example, use <code>&amp;nbsp</code> instead of <code>&nbsp;</code>. In Atom, this requires the use of the <code>type="html"</code> attribute on the construct.</p>
<p>One solution that <b>is</b> widely supported is to replace the use of named entity references with their <a href="http://www.w3.org/TR/REC-xml/#sec-entity-decl">numerical equivalents</a>. For example, use <code>&#160</code> or <code>&#xa0;</code> instead of <code>&nbsp;</code>. A complete list of XHTML characters and their numeric equivalents can be found <a href="http://www.w3.org/TR/xhtml1/dtds.html#a_dtd_Latin-1_characters">here</a>. Many programming languages have libraries that can assist with this task.</p>
<p>Another approach it to make use of entity-encoded HTML. For example, use <code>&amp;nbsp</code> instead of <code>&nbsp;</code>. In Atom, this requires the use of the <code>type="html"</code> attribute on the construct.</p>