The more-Tag have a filter, you can enhance this with a small plugin like the follow example.
<?php
/**
* Plugin Name: br after more-Tag
* Description: Add content of var $extra_more after more-Tag
* Version: 0.0.1
*/
! defined( 'ABSPATH' ) and exit;
add_filter( 'the_content_more_link', 'custom_more_link', 9999 );
function custom_more_link( $more_link ) {
$extra_more = '<br>'; // here add your break
return $more_link . $extra_more;
}
If you will replace the more tag with your markup, then use a small plugin and preg_replace
.
add_filter( 'the_content', 'fb_more_link' );
function fb_more_link( $content ) {
// only on single posts
if ( ! is_single() )
return $content;
// adsense code
$my_content = '<br>';
// replace more tag
$content = preg_replace('/<span id\=\"(more\-\d+)"><\/span>/', $my_content, $content);
return $content;
}
$maxchar=(strpos($content, '<!--more-->'))?strpos(preg_replace('/<.*?>/', '', preg_replace('/<!--more-->/','@smt_readmore_tag',$content)), '@smt_readmore_tag'):$maxchar;