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Remove HTML comment usage in data blocks
JSON-LD script elments MUST only contain valid JSON. HTML entity-based character encoding is used to avoid accidental script tag parsing problems--as described in the note in Restrictions for contents of <script> elements: https://www.w3.org/TR/html52/semantics-scripting.html#restrictions-for-contents-of-script-elements
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‎index.html

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@@ -8677,46 +8677,29 @@ <h3>Graph Containers</h3>
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<a data-cite="HTML52/infrastructure.html#dynamic-changes-to-base-urls">Dynamic changes to base URLs</a>.</p>
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<section><h3>Restrictions for contents of JSON-LD <code>script</code> elements</h3>
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<p class="issue atrisk">As HTML entities and comments are not allowable in
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JSON, the use of comments, escapes,
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and <a data-cite="HTML5/syntax.html#character-references">HTML Character references</a>
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is subject to further discussion in the Working Group.</p>
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<p class="issue atrisk">This section adds additional requirements for escaping
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certain JSON values when embedding that JSON within HTML. This approach
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is consequently subject to further discussion in the Working Group.</p>
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<p>Depending on how the HTML document is served, certain strings may need
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to be escaped. In particular, the content MAY be enclosed
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in the HTML <em>comment-open</em> (<code>&lt;!--</code>) and <em>comment-close</em> (<code>--&gt;</code>) text sequences.</p>
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<p>As described in HTML <a data-cite="HTML52/semantics-scripting.html#restrictions-for-contents-of-script-elements">Restrictions for contents of <code>&lt;script&gt;</code> elements</a>
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the <a data-cite="DOM#dom-node-textcontent">textContent</a> of a script element may include balanced comments
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and other text which complicate extracting the JSON-LD content from a <a data-cite="HTML52/semantics-scripting.html#data-block">data blocks</a>.
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JSON-LD places further restrictions on the contents of
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<a data-cite="HTML52/semantics-scripting.html#the-script-element">script elements</a> containing JSON-LD.</p>
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<p>A JSON-LD script element MAY begin with an optional <em>comment-open</em> surrounded by any amount of <a data-cite="HTML52/infrastructure.html#space-characters">space characters</a>,
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followed by valid JSON and ending with an optional <em>comment-close</em> surrounded by any amount of <a data-cite="HTML52/infrastructure.html#space-characters">space characters</a>.
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Any content within the JSON content which can be confused with a <em>comment-open</em>, <em>script-open</em>,
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<em>comment-close</em>, or <em>script-close</em> MUST be escaped using a REVERSE SOLIDUS (<code>\</code>) character
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as follows:</p>
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<ul>
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<li><code>&lt;!--</code> → <code>&lt;\!--</code></li>
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<li><code>&lt;script</code> → <code>&lt;\script</code></li>
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<li><code>--&gt;</code> → <code>--\&gt;</code></li>
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<li><code>&lt;/script</code> → <code>&lt;\/script</code></li>
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</ul>
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<p>Additionally, content of a script element MAY be escaped using <a data-cite="HTML5/syntax.html#character-references">HTML Character references</a>, such as the following:</p>
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to be escaped to prevent disrupting the HTML parsing algorithm.</p>
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<p>Due to the HTML <a data-cite="HTML52/semantics-scripting.html#restrictions-for-contents-of-script-elements">Restrictions for contents of <code>&lt;script&gt;</code> elements</a>
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additional encoding restrictions are placed on JSON-LD data contained in
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<a data-cite="HTML52/semantics-scripting.html#the-script-element">script elements</a>.</p>
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<p>A JSON-LD script element MUST contain only valid JSON.
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Any strings within the JSON content which contains text which can be confused with a <em>comment-open</em>, <em>script-open</em>,
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<em>comment-close</em>, or <em>script-close</em> MUST be escaped using <a data-cite="HTML5/syntax.html#character-references">HTML Character references</a>, such as the following:</p>
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<ul>
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<li><code>&amp;amp;</code> → &amp; (<a href="/wiki/Ampersand" title="Ampersand">ampersand</a>, U+0026)</li>
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<li><code>&amp;lt;</code> → &lt; (less-than sign, U+003C)</li>
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<li><code>&amp;gt;</code> → &gt; (greater-than sign, U+003E)</li>
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<li><code>&amp;quot;</code> → " (quotation mark, U+0022)</li>
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<li><code>&amp;apos;</code> → ' (apostrophe, U+0027)</li>
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</ul>
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<p>JSON-LD Processors MUST remove surrounding <em>comment-open</em> and <em>comment-close</em>
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sequences, unescape any escaped <em>comment-open</em>, <em>comment-close</em>,
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<em>script-open</em>, and <em>script-close</em> sequences,
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and turn <a data-cite="HTML5/syntax.html#character-references">HTML Character references</a> into the corresponding Unicode.
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</p>
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<aside class="example ds-selector-tabs"
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title="Embedding JSON-LD in HTML with comments">
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title="Embedding JSON-LD containing HTML in HTML">
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<div class="selectors">
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<button class="selected" data-selects="original">Original</button>
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<button data-selects="expanded">Expanded</button>
@@ -8727,15 +8710,12 @@ <h3>Graph Containers</h3>
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data-content-type="text/html">
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<!--
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<script type="application/ld+json">
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< ! - -
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{
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"@context": "https://json-ld.org/contexts/person.jsonld",
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"@id": "http://dbpedia.org/resource/John_Lennon",
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"name": "John Lennon",
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"born": "1940-10-09",
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"spouse": "http://dbpedia.org/resource/Cynthia_Lennon"
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"@context": "http://schema.org/",
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"@type": "WebPageElement",
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"name": "Encoding Issues",
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"description": "Issues list such as unescaped &lt;/script&gt; or --&gt;"
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}
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- - >
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</script>
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-->
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</pre>
@@ -8744,13 +8724,10 @@ <h3>Graph Containers</h3>
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data-result-for="Embedding JSON-LD in HTML with comments-original">
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<!--
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[{
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"@id": "http://dbpedia.org/resource/John_Lennon",
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"http://xmlns.com/foaf/0.1/name": [{"@value": "John Lennon"}],
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"http://schema.org/birthDate": [
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{"@value": "1940-10-09", "@type": "http://www.w3.org/2001/XMLSchema#date"}
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],
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"http://schema.org/spouse": [
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{"@id": "http://dbpedia.org/resource/Cynthia_Lennon"}
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"@type": "http://schema.org/WebPageElement",
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"http://schema.org/name": [{"@value": "Encoding Issues"}],
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"http://schema.org/description": [
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{"@value": "Issues list such as unescaped &lt;/script&gt; or --&gt;"}
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]
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}]
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-->
@@ -8760,9 +8737,8 @@ <h3>Graph Containers</h3>
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data-to-rdf>
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<thead><tr><th>Subject</th><th>Property</th><th>Value</th><th>Value Type</th></tr></thead>
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<tbody>
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<tr><td>http://dbpedia.org/resource/John_Lennon</td><td>foaf:name</td><td>John Lennon</td><td>&nbsp;</td></tr>
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<tr><td>http://dbpedia.org/resource/John_Lennon</td><td>schema:birthDate</td><td>1940-10-09</td><td>xsd:date</td></tr>
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<tr><td>http://dbpedia.org/resource/John_Lennon</td><td>schema:spouse</td><td>http://dbpedia.org/resource/Cynthia_Lennon</td><td>&nbsp;</td></tr>
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<tr><td>_:b0</td><td>schema:name</td><td>Encoding Issues</td><td>&nbsp;</td></tr>
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<tr><td>_:b0</td><td>schema:description</td><td>Issues list such as unescaped &amp;lt;/script&amp;gt; or --&amp;gt;</td><td>&nbsp;</td></tr>
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</tbody>
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</table>
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<pre class="turtle"
@@ -8771,13 +8747,10 @@ <h3>Graph Containers</h3>
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data-result-for="Embedding JSON-LD in HTML with comments-expanded"
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data-to-rdf>
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<!--
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@prefix foaf: <http://xmlns.com/foaf/0.1/> .
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@prefix schema: <http://schema.org/> .
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@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
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<http://dbpedia.org/resource/John_Lennon> foaf:name "John Lennon";
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schema:birthDate "1940-10-09"^^xsd:date;
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schema:spouse <http://dbpedia.org/resource/Cynthia_Lennon> .
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<> schema:name "Encoding Issues";
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schema:description "Issues list such as unescaped &lt;/script&gt; or --&gt;" .
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-->
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</pre>
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</aside>

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