core-bundle/src/Resources/contao/library/Contao/StringUtil.php
public static function highlight($strString, $strPhrase, $strOpeningTag='<strong>', $strClosingTag='</strong>')
	{
		if ($strString == '' || $strPhrase == '')
		{
			return $strString;
		}

		return preg_replace('/(' . preg_quote($strPhrase, '/') . ')/i', $strOpeningTag . '\\1' . $strClosingTag, $strString);
	}
public static function highlight($strString, $strPhrase, $strOpeningTag='<strong>', $strClosingTag='</strong>')
	{
		if ($strString == '' || $strPhrase == '')
		{
			return $strString;
		}

		return preg_replace('/(' . preg_quote($strPhrase, '/') . ')/i', $strOpeningTag . '\\1' . $strClosingTag, $strString);
	}
Highlight a phrase within a string

@param string $strString     The string
@param string $strPhrase     The phrase to highlight
@param string $strOpeningTag The opening tag (defaults to <strong>)
@param string $strClosingTag The closing tag (defaults to </strong>)

@return string The highlighted string