Writing a custom excerpt function

I want this because:

1-) I have a list item ol /ol at the start of my every post.

2-) When wordpress shows summary of the post it reads some words from the beginning of the post.

3-) This causes the summary to be comprised of the navigation list of the post. The words from inside the ol /ol tags.

4-) I don’t want the words from ol tags in my excerpt. I want it to directly go beyond the /ol tags for the excerpt content.

My code is:

function custom_excerpt($text) {
    $pos = strpos($text, '</ol>');
    $text = substr($text, $pos);
    return $text;
}
add_filter('the_excerpt', 'custom_excerpt');

This doesn’t work. I guess the tags are already stripped so “strpos” can’t find anything. But even i return “…” from function, the same text as before stays. Like my custom function has no effect. Why is that? Is the theme’s functions somehow interferes with the excerpt code?

The easiest way is to use strip_tags().

// Remove all html from the excerpt.
function custom_excerpt( $text ) {
    return strip_tags( $text );
}
add_filter( 'the_excerpt', 'custom_excerpt' );

If you want to get fancy and trim the excerpt length, you can use this function.

// Trim default excerpt length from 55 chars to 20. 
function custom_excerpt_length( $length ) {
    return 20;
}
add_filter( 'excerpt_length', 'custom_excerpt_length', 99 );