One of the most common mistakes is editing functions.php of your theme file. You should almost never do that because of many reasons. Instead, you should make it a habit to create a simple “functionality plugin” for every WordPress site you build.
Let’s say your goal is simply to add a google analytics code for your “Mad Hatter Hats” site.
- It’s a good idea to prefix your functions with a short unique word. Let’s say your prefix will be “mhat_“
- You could use a simple madhat-site-plugin.php in ./plugins folder, however its also a good idea to put it inside a folder, in case you need to put more stuff in there like custom scripts and styles.
- You might want to add a TextDomain for your plugin in case you wanna use translatable strings like in template tag functions.
So, you’d go on and create a folder and a file, ./wp-content/plugins/madhat-site/madhat-site-plugin.php with the content:
<?php
/*
Plugin Name: Mad Hatter Site Functions
Description: Site Functions
Author: The Hatter
Version: 1.0
Text Domain: mhat_lang
*/
function mhat_ga_code() {
?>
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-XXXXXXXX-1', 'auto');
ga('send', 'pageview');
</script>
<?php
}
add_action( 'wp_footer', 'mhat_ga_code')
?>
You might want to check out these sources too:
* http://codex.wordpress.org/Child_Themes
* https://css-tricks.com/wordpress-functionality-plugins/
* http://wpninjas.com/how-to-create-a-simple-wordpress-plugin/