What are some common WYSIWYG editors used for PHP websites and how can they be integrated into existing forms?

Many common WYSIWYG editors used for PHP websites include TinyMCE, CKEditor, and Summernote. These editors can be easily integrated into existing forms by including the necessary JavaScript and CSS files, initializing the editor on the textarea element, and processing the submitted content on the server side.

<!-- Include the necessary JavaScript and CSS files for the WYSIWYG editor -->
<script src="https://cdn.ckeditor.com/4.16.1/standard/ckeditor.js"></script>
<link rel="stylesheet" href="https://cdn.ckeditor.com/4.16.1/standard/ckeditor.css">

<!-- Initialize the CKEditor on the textarea element -->
<textarea name="content" id="editor"></textarea>
<script>
    CKEDITOR.replace('editor');
</script>

<?php
// Process the submitted content
if(isset($_POST['submit'])){
    $content = $_POST['content'];
    // Further processing or saving the content to database
}
?>