Insert any Code Before H2

Hi there,

You can try something like this:

add_filter( 'the_content', 'insert_element', 20 );
function insert_element( $content ) {
    global $post;
    $inserted_element = 'your ads here';
    if ( is_single() && ! is_admin() ) {
        return prefix_insert_after_h2( $inserted_element, 1, $content );
    }
    return $content;
}
function prefix_insert_after_h2( $insertion, $h2_id, $content ) {
  $closing_h2 = '</h2>';
  $h2s = explode( $closing_h2, $content );
  foreach ($h2s as $index => $h2) {
    if ( trim( $h2 ) ) {
     $h2s[$index] .= $closing_h2.$insertion;
    }
  }
  return implode( '', $h2s );
}

Replace the line your ads here with whatever element you want to add in. :)

Thanks, Elvin. But how can I exclude page, specific category or tags? (Sorry, I'm not a coder)

Modify this condition:

if ( is_single() && ! is_admin() )

Add in_category() for category checking.
https://developer.wordpress.org/reference/functions/in_category/

Add has_tag() for post tag checking.
https://developer.wordpress.org/reference/functions/has_tag/

Example condition: posts with dogs category or cute tag.
if ( ! is_admin() && is_single() || has_tag('cute') || in_category('dogs') )

And for page exclusion?

You'll have to modify the code and add an exclusion condition.

Example:

add_filter( 'the_content', 'insert_element', 20 );
function insert_element( $content ) {
    global $post;
    $exclusion = array(123,456,789);
    $inserted_element = 'your ads here';
    if ( is_single() && ! is_admin() ) {
        if(in_array( $post->ID, $exclusion )){
            return;
        }
        else {
            return prefix_insert_after_h2( $inserted_element, 1, $content );
        }
    }
    return $content;
}
function prefix_insert_after_h2( $insertion, $h2_id, $content ) {
  $closing_h2 = '</h2>';
  $h2s = explode( $closing_h2, $content );
  foreach ($h2s as $index => $h2) {
    if ( trim( $h2 ) ) {
     $h2s[$index] .= $closing_h2.$insertion;
    }
  }
  return implode( '', $h2s );
}

You then modify the array values in $exclusion = array(123,456,789); to the page ids to be excluded.