In this chapter, we will cover the following topics:
- Creating a plugin file and header
- Adding output content to page headers using plugin actions
- Using WordPress path utility functions to load external files and images
- Modifying the site generator meta tag using plugin filters
- Adding text after each item's content using plugin filters
- Inserting link statistics tracking code in page body using plugin filters
- Troubleshooting coding errors and printing variable content
- Creating a new simple shortcode
- Creating a new shortcode with parameters
- Creating a new enclosing shortcode
- Loading a style sheet to format plugin output
- Writing plugins using object-oriented PHP
