block/HtmlTrait.php
protected function identifyHtml($line, $lines, $current)
	{
		if ($line[0] !== '<' || isset($line[1]) && $line[1] == ' ') {
			return false; // no html tag
		}

		if (strncmp($line, '<!--', 4) === 0) {
			return true; // a html comment
		}

		$gtPos = strpos($lines[$current], '>');
		$spacePos = strpos($lines[$current], ' ');
		if ($gtPos === false && $spacePos === false) {
			return false; // no html tag
		} elseif ($spacePos === false) {
			$tag = rtrim(substr($line, 1, $gtPos - 1), '/');
		} else {
			$tag = rtrim(substr($line, 1, min($gtPos, $spacePos) - 1), '/');
		}

		if (!ctype_alnum($tag) || in_array(strtolower($tag), $this->inlineHtmlElements)) {
			return false; // no html tag or inline html tag
		}
		return true;
	}
protected function identifyHtml($line, $lines, $current)
	{
		if ($line[0] !== '<' || isset($line[1]) && $line[1] == ' ') {
			return false; // no html tag
		}

		if (strncmp($line, '<!--', 4) === 0) {
			return true; // a html comment
		}

		$gtPos = strpos($lines[$current], '>');
		$spacePos = strpos($lines[$current], ' ');
		if ($gtPos === false && $spacePos === false) {
			return false; // no html tag
		} elseif ($spacePos === false) {
			$tag = rtrim(substr($line, 1, $gtPos - 1), '/');
		} else {
			$tag = rtrim(substr($line, 1, min($gtPos, $spacePos) - 1), '/');
		}

		if (!ctype_alnum($tag) || in_array(strtolower($tag), $this->inlineHtmlElements)) {
			return false; // no html tag or inline html tag
		}
		return true;
	}
identify a line as the beginning of a HTML block.