php 输出原样代码
https://www.php.net/manual/zh/language.types.string.php#language.types.string.syntax.nowdoc
<?php
echo <<<'EOD'
<?php phpinfo();?>
EOD;
会输出文本
<?php phpinfo();?>
https://www.php.net/manual/zh/language.types.string.php#language.types.string.syntax.nowdoc
<?php
echo <<<'EOD'
<?php phpinfo();?>
EOD;
会输出文本
<?php phpinfo();?>
