Get and Edit HTML Using WordPress API Hooks

How to Get and Edit HTML Using WordPress API Hooks

This article introduces how to get the final HTML after various processes and filters are complete using WordPress API hooks in PHP, then edit and modify it with PHP before rendering.

Overview

To edit the HTML that is finally displayed in WordPress, use ob_start("callback");. This method is especially effective when you want to modify HTML output from plugins that don’t have hooks prepared, or when you want to dynamically change HTML tags and their contents. Since you’ll be editing HTML using regular expressions, it takes some effort, but if this is the only way, you have to use it.

Note

If you want to change HTML DOM elements, it may be more efficient to use JavaScript to manipulate them after the page loads.

Usage

Copy and paste the following PHP code into header.php or functions.php. This code basically does nothing, but it also shows a sample of how to change image alt attributes.

<?php

function callback($buffer) {
    // Replace all "site" with "site"
    // return str_replace("サイト", "サイト", $buffer);

    // Sample to change image alt attributes to "hogehoge"
    // $buffer = preg_replace('/alt=".*"/', 'alt="hogehoge"', $buffer);

    return $buffer;
}

ob_start("callback");

?>

Sample Code Explanation

• callback function: This function edits the output buffer content.
  • As an example, code using preg_replace to change image alt attributes is commented out. If you enable this code, all image tag alt attributes will be changed to “hogehoge”.
• ob_start(“callback”): This function starts output buffering and processes the buffer content using the specified callback function.

Note

You may need to change preg_replace to preg_replace_all as needed. Check the regular expression reference and use the appropriate function.

This concludes the introduction to getting and editing HTML using WordPress API hooks. Customize the sample code as needed and apply it to your actual projects.