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function is not described

wp_replace_in_html_tags() WP 4.2.3

Replace characters or phrases within HTML elements only.

No Hooks.

Return

String. The formatted text.

Usage

wp_replace_in_html_tags( $haystack, $replace_pairs );
$haystack(string) (required)
The text which has to be formatted.
$replace_pairs(array) (required)
In the form array('from' => 'to', ...).

Code of wp replace in html tags: wp-includes/formatting.php VER 5.1.1

<?php
function wp_replace_in_html_tags( $haystack, $replace_pairs ) {
	// Find all elements.
	$textarr = wp_html_split( $haystack );
	$changed = false;

	// Optimize when searching for one item.
	if ( 1 === count( $replace_pairs ) ) {
		// Extract $needle and $replace.
		foreach ( $replace_pairs as $needle => $replace ) {
		}

		// Loop through delimiters (elements) only.
		for ( $i = 1, $c = count( $textarr ); $i < $c; $i += 2 ) {
			if ( false !== strpos( $textarr[ $i ], $needle ) ) {
				$textarr[ $i ] = str_replace( $needle, $replace, $textarr[ $i ] );
				$changed       = true;
			}
		}
	} else {
		// Extract all $needles.
		$needles = array_keys( $replace_pairs );

		// Loop through delimiters (elements) only.
		for ( $i = 1, $c = count( $textarr ); $i < $c; $i += 2 ) {
			foreach ( $needles as $needle ) {
				if ( false !== strpos( $textarr[ $i ], $needle ) ) {
					$textarr[ $i ] = strtr( $textarr[ $i ], $replace_pairs );
					$changed       = true;
					// After one strtr() break out of the foreach loop and look at next element.
					break;
				}
			}
		}
	}

	if ( $changed ) {
		$haystack = implode( $textarr );
	}

	return $haystack;
}