PHP functions to insert content between or after HTML paragraphs the right way, without using regular expressions.

Insert content in a string containing HTML markup. The PHP DOM module is used to find and add the content after paragraphs.

• Insert content after the middle paragraph (default)
• Insert content after a set number of paragraphs
• Insert content after every number of paragraphs
• Exclude nested paragraphs (default)
• Inserted content can contain HTML as well.

Only top-level (non nested) HTML paragraphs are used to add content after. Let's say you wanted to add content after the second paragraph in this content.

<div>a div with content</div>
<p>first top-level paragraph</p>
<blockquote>
	<p>This is a nested paragraph</p><!-- not a top-level paragraph -->
</blockquote>
<p>second top-level paragraph</p>
<!-- Content should be inserted here -->
<p>third top-level paragraph</p>

Most functions (or scripts) that are similar to this one would wrongly add your content ater the second <p> inside the <blockquote> element.

• Set the top_level_p_only argument to false to include nested paragraphs as well.
• Use the parent_element_id argument to only include top-level paragraphs (nested) in an HTML element with a specific id. Set the top_level_p_only attribute (from above) to false to also include nested paragraphs found in that HTML element.

By default content is inserted after the middle paragraph. In other words, if the HTML content contains four paragraphs it will be inserted after the second.

• Use the insert_after_p argument to insert content after a number of paragraphs instead of in the middle.
• Or use the insert_every_p argument to insert content after every number of paragraphs instead of in the middle.

The content you want to insert will be added at the end if no paragraphs were found. Equally so, if you've set it to insert content after a set number of paragraphs, and not enough paragraphs were found, it's inserted after the last found paragraph. If you're using the parent_element_id argument and no paragraphs are found in that element the content will be inserted after the parent element.

• Set the insert_if_no_p argument to false to not append content if no (or not enough) paragraphs are found.

The inserted content will be wrapped in a HTML paragraph element <p></p> by default.

• Use the insert_element argument to wrap the inserted content in any other block-level HTML element.

Include the insert-content.php file in your project to make use of the insert_content() function. Or require it in your project with composer require keesiemeijer/insert-content

<?php
require 'path/to/insert-content.php';

echo keesiemeijer\Insert_Content\insert_content( $content, $insert_content, $args ); 
?>

The defaults for the optional arguments ($args) are:

$args = array(
	'parent_element_id' => '',
	'insert_element'   => 'p',
	'insert_after_p'   => '',
	'insert_every_p'   => '',
	'insert_if_no_p'   => true,
	'top_level_p_only' => true,
);

• $content (string)(required) String of content (with paragraphs) you want to add content in between.
• $insert_content (string) String of content you want to insert.
• $args (array) Array with optional arguments
  • parent_element_id (string) Parent element id (without #) to search paragraphs in. Default: empty string. Search for paragraphs in the entire content.
  • insert_element (string) Block-level HTML element the inserted content ($insert_content) is wrapped in. Default: 'p'. (e.g. 'p', 'div', etc.)
  • insert_after_p (int) Insert content after a number of paragraphs. Default: empty string. The content is inserted after the middle paragraph.
  • insert_every_p (int) Insert content after every number of paragraphs. Default: empty string. The content is inserted after the middle paragraph.
  • insert_if_no_p (boolean) Insert content even if the required number of paragraphs from insert_after_p (above) are not found. Default: true. Insert after the last paragraph. (inserts after the content if no paragraphs are found).
  • top_level_p_only (boolean) Insert content after top level paragraphs only. Default: true (recommended)

Add content after the second paragraph in this content:

<div>a div with content</div>
<p>first top-level paragraph</p>
<blockquote>
	<p>This is a nested paragraph</p><!-- not a top-level paragraph -->
</blockquote>
<p>second top-level paragraph</p>
<p>third top-level paragraph</p>

For this example pretend the above HTML content is stored inside the $content variable.

<?php
$args = array(
	'insert_after_p' => 2, // Insert after the second paragraph
);

// Content you want to insert (without the parent element HTML tag)
$insert_content = 'I was inserted after the <strong>second</strong> paragraph';

echo keesiemeijer\Insert_Content\insert_content( $content, $insert_content, $args );
?>

The output for this example is this.

<div>a div with content</div>
<p>first top-level paragraph</p>
<blockquote>
	<p>This is a nested paragraph</p><!-- not a top-level paragraph -->
</blockquote>
<p>second top-level paragraph</p>
<p>I was inserted after the <strong>second</strong> paragraph</p>
<p>third top-level paragraph</p>

Add content after the second paragraph in an HTML element with the id specific-id.

<p>first paragraph</p>
<p>second paragraph</p>
<div id='specific-id'>
	<p>first top-level paragraph inside the targeted element</p>
	<p>second top-level paragraph inside the targeted element</p>
	<p>third top-level paragraph inside the targeted element</p>
</div>
<p>third paragraph</p>

For this example pretend the above HTML content is stored inside the $content variable.

<?php
$args = array(
	'parent_element_id' => 'specific-id'
	'insert_after_p'    => 2, // Insert after the second paragraph
);

// Content you want to insert (without the parent element HTML tag)
$insert_content = 'I was inserted after the <strong>second</strong> paragraph inside the targeted element';

echo keesiemeijer\Insert_Content\insert_content( $content, $insert_content, $args );
?>

The output for this example is this.

<p>first paragraph</p>
<p>second paragraph</p>
<div id='specific-id'>
	<p>first top-level paragraph inside the targeted element</p>
	<p>second top-level paragraph inside the targeted element</p>
	<p>I was inserted after the <strong>second</strong> paragraph inside the targeted element</p>
	<p>third top-level paragraph inside the targeted element</p>
</div>
<p>third paragraph</p>