WP_HTML_Processor::normalize( string $html ): string|null

This method assumes that the given HTML snippet is found in BODY context.For normalizing full documents or fragments found in other contexts, create a new processor using WP_HTML_Processor::create_fragment or WP_HTML_Processor::create_full_parser and call WP_HTML_Processor::serialize on the created instances. Many aspects of an input HTML fragment may be changed during normalization. <ul> <li>Attribute values will be double-quoted.</li> <li>Duplicate attributes will be removed.</li> <li>Omitted tags will be added.</li> <li>Tag and attribute name casing will be lower-cased, except for specific SVG and MathML tags or attributes.</li> <li>Text will be re-encoded, null bytes handled, and invalid UTF-8 replaced with U+FFFD.</li> <li>Any incomplete syntax trailing at the end will be omitted, for example, an unclosed comment opener will be removed.</li> </ul> Example: echo WP_HTML_Processor::normalize( '&lt;a href=#anchor v=5 href="/" enabled&gt;One&lt;/a another v=5&gt;&lt;!--' ); // &lt;a href="#anchor" v="5" enabled&gt;One&lt;/a&gt; echo WP_HTML_Processor::normalize( '&lt;div&gt;&lt;/p&gt;fun&lt;table&gt;&lt;td&gt;cell&lt;/div&gt;' ); // &lt;div&gt;&lt;p&gt;&lt;/p&gt;fun&lt;table&gt;&lt;tbody&gt;&lt;tr&gt;&lt;td&gt;cell&lt;/td&gt;&lt;/tr&gt;&lt;/tbody&gt;&lt;/table&gt;&lt;/div&gt; echo WP_HTML_Processor::normalize( '&lt;![CDATA[invalid comment]]&gt; syntax &lt; &lt;&gt; "oddities"' ); // &lt;!--[CDATA[invalid comment]]--&gt; syntax &amp;lt; &amp;lt;&amp;gt; &amp;quot;oddities&amp;quot;