wpAutop – can't disable it

Javascript in a post? Remove all white space in the script and the WP editor won’t add paragraph returns.

Or make a shortcode: http://codex.wordpress.org/Shortcode_API

Put in functions.php and then put the <!-- noformat on --> and <!-- noformat off --> tags around post/page content you don’t want formatted by the editor.

// <!-- noformat on --> and <!-- noformat off --> functions

function newautop($text)
{
	$newtext = "";
	$pos = 0;

	$tags = array('<!-- noformat on -->', '<!-- noformat off -->');
	$status = 0;

	while (!(($newpos = strpos($text, $tags[$status], $pos)) === FALSE))
	{
		$sub = substr($text, $pos, $newpos-$pos);

		if ($status)
			$newtext .= $sub;
		else
			$newtext .= convert_chars(wptexturize(wpautop($sub)));		//Apply both functions (faster)

		$pos = $newpos+strlen($tags[$status]);

		$status = $status?0:1;
	}

	$sub = substr($text, $pos, strlen($text)-$pos);

	if ($status)
		$newtext .= $sub;
	else
		$newtext .= convert_chars(wptexturize(wpautop($sub)));		//Apply both functions (faster)

	//To remove the tags
	$newtext = str_replace($tags[0], "", $newtext);
	$newtext = str_replace($tags[1], "", $newtext);

	return $newtext;
}

function newtexturize($text)
{
	return $text;
}

function new_convert_chars($text)
{
	return $text;
}

remove_filter('the_content', 'wpautop');
add_filter('the_content', 'newautop');

remove_filter('the_content', 'wptexturize');
add_filter('the_content', 'newtexturize');

remove_filter('the_content', 'convert_chars');
add_filter('the_content', 'new_convert_chars');