我怎样才能在wordpress textarea中使用php代码？

I want to use the following code inside the Wordpress textarea :

if(get_post_meta($post->ID, "embed", true)):

echo  ' ';

endif;

How can I do it ?

What textarea is it exactly? The one from writing a new article?

If you're trying to use it there you could define your php as a shortcode in your functions.php and use the shortcode in the textarea afterwards.

http://codex.wordpress.org/Function_Reference/add_shortcode

And I guess there are plugins to execute php in articles but I don't think it's recommendable.

Use the normal php syntax for this <?php //....code.... ?>

For PHP in TXT widgets :

    function execute_php($html){
     if(strpos($html,"<"."?php")!==false){
          ob_start();
          eval("?".">".$html);
          $html=ob_get_contents();
          ob_end_clean();
     }
     return $html;
}

add_filter('widget_text','execute_php',100);

Inside the Editor, just use normal php code ( <?php //my_code ?> ) but make sure you are in text mode not visual mode